Mark Gatiss has penned two episodes for the new series of 'Doctor Who'.
The acclaimed writer-and-actor will return to the BBC sci-fi drama to write two episodes for the upcoming eighth series, which will see Peter Capaldi make his debut as the Twelfth Doctor.
Mark said during a recent promotional trip to Brazil on behalf of BBC Worldwide: "I am writing for Peter Capaldi - two episodes, in fact."
The 'Sherlock' writer has previously written six episodes of 'Doctor Who' and appeared in a 2007 episode of the series as Professor Lazarus.
Mark also penned BBC Two's 'Doctor Who' origins drama 'An Adventure in Space and Time', which aired last November as part of the show's 50th anniversary celebrations.
The writer recently praised Peter Capaldi's portrayal of the Doctor and feels he will bring new energy to the role.
He said: "Peter has a very different energy to Matt Smith and to David Tennant. He's older which changes everything ... it's amazing what a change does!
"Matt was sublime and I was very sorry to see him go, but it's also great to have a change, as it has always been with the Doctor."

Michelle Collins is joining 'Casualty'.
The 51-year-old actress, who is to leave her role as Stella Price in 'Coronation Street' later this year, will be back on screens just a few weeks later in the BBC One medical drama.
Michelle has agreed to a short role in the show as a love interest to paramedic Jeff Collier, played by Matt Bardock.
She told The Sun newspaper: "I'm pleased to be out of a soap for now. I have more time to be a mum and I'm going into 'Casualty' as a key character's love interest.
"It is only for a few weeks, which is perfect."
Michelle's character Samantha will end up in hospital after rushing to the aid of a dad who has a heart attack while running a race with his son.
The actress will be on screens in early July - just weeks after her character exits Manchester-based 'Corrie'.
Michelle stunned producers last year when she announced her decision to quit the show due to unhappiness with her lack of storylines, as well as the long commute from her home in London to the 'Corrie' set in Manchester.
She said recently: "I threw myself wholeheartedly into 'Corrie' but I ended up spreading myself far too thinly.
"The tiredness is the worst, it can make you a zombie. Work is fantastic, but it's not the be-all and end-all."

'Coronation Street' legend Liz Dawn admits her biggest regret is not leaving the soap sooner.
The 74-year-old actress - who played Vera Duckworth on-and-off from 1974 until 2010 - officially turned her back on the cobbles eight years ago after incurable lung disease emphysema forced her to retire.
However, the screen star - who made a brief one-off return in 2010 as a ghost - believes she should have left the soap long before she did because she was struggling immensely.
Liz explained: "I wish I had left before.
"It was a bit of a struggle. Some days I would have to sit in the car for about 10 minutes before I had the energy to even start the engine.
"And then your memory goes. I used to have more and more notes on that table in the Duckworths' living room."
Liz admits it was her co-star Bill Tarmey - who played her on-screen husband Jack Duckworth - that got her through the physical challenges on set.
She said: "To be honest, I don't know how anybody can stay in a soap for 34 years. You would have to be mental. It takes over your life. Especially Jack and Vera."
Bill sadly passed away at his holiday home in Tenerife in 2012 after suffering from a heart attack, but Liz insists he will always remain in her heart.
She told the Daily Mirror newspaper: "Ah Bill, I miss him you know.
"I have him in my purse, I carry a picture of him with me always. Every scene I filmed with Bill was a treat."

Louis Walsh is starting a campaign to get Sharon Osbourne back on 'The X Factor'.
The 61-year-old music mogul thinks the talent show benefits from having feisty Sharon on the judging panel and although she has ruled herself out of returning for this year's series, Louis is hoping he can persuade her to come back.
When asked who he wants to join Simon Cowell and Cheryl Cole on the judging panel, he told BANG Showbiz: "I love Sharon Osbourne, she'd be my number one (pick). Get Sharon back, start the campaign! Get Sharon back!"
Louis has been a part of the judging panel since the series first started in 2004, but he claims he hasn't yet been told by Simon - who, along with Cheryl, is returning to the programme after four years away - if he is going to be a judge this year.
Louis insists he will only help care for Simon's baby son Eric - his first child with Lauren Silverman - if he is named on the panel.
Speaking at the opening night of 'The X Factor' musical 'I Can't Sing' at the London Palladium on Wednesday evening (27.03.14), he said: "I honestly don't know if I'm coming back. I tell you what, I'll do the babysitting if he gives me the job (on 'The X Factor')."
'I Can't Sing' is a spoof of the talent show, written by Harry Hill and Steve Brown, and judges Simon, Cheryl and Louis, as well 'X Factor' host Dermot O'Leary, are parodied in it.
Louis has no problem with being ridiculed in the stage production - which is now open to the public - but he's not surprised that a younger actor, Nigel Harman, 40, has been cast as Simon, 54.
Louis said: "Nigel looks much younger than Simon, he's a better singer, he's a better dancer and he doesn't have the ego, but he does look a lot like him in the show.
"How come Simon got someone really young to play him and somebody much older to play me? Have you seen my character in the show? I'm not that bad! But I just go with it you know, it's funny."

Holt McCallany is set to star in 'Monster Trucks'.
The 49-year-old actor will play a dangerous security contractor who is determined to get his job done, according to deadline.com.
He will join 'X‑Men: First Class' actor Lucas Till, Suburgatory's Jane Levy and US 'The Office' star Amy Ryan.
Till has been negotiating the role of a ''bad boy with a good heart'', while Levy will play a girl who is ''what one might imagine Tina Fey was like in high school" and Ryan has been cast as a single mum who is trying to make ends meet while raising her teenage son.
'Kung Fu Panda' writers Jonathan Aibel and Glenn Berger will pen the script while Mary Parent is producing the Chris Wedge-directed film through her Disruption Entertainment banner.
Production for 'Monster Trucks' is expected to start this summer and it is due for release in May 2015.
McCallany will next hit the big screen on 'Run All Night', opposite Liam Neeson, Joel Kinnaman and Ed Harris, to help tell the story of an ageing hitman who is forced to take on his brutal former boss to protect his estranged son and his family.

Joseph Fiennes has joined the cast of 'Strangerland'. The 43-year-old actor is set to star as Nicole Kidman's husband in the upcoming mystery drama, which will follow them as their lives unravel after their two teenage children go missing in the dese...

Pierce Brosnan has agreed to star in "the next" 'Expendables' film.
The 60-year-old actor has been offered a part in the action films - which have been written by and star Sylvester Stallone - by producer Avi Lerner, who would "love" to work with the hunk.
Talking to ShortList magazine, he said: "The offer has come in for the next 'Expendables'. I just worked over in Bulgaria with Avi Lerner who makes them. He said 'Would you like to be in 'The Expendables'? I'd love to have you', and I said 'Why not?'. So we'll see."
Quizzed on what film in the franchise he's referring to, the Hollywood A-Lister added: "I have no idea which one it would be, I just said 'Yes'. It could be seven!"
'The Expendables' was released in 2010 and proved to be commercially successful, and two years later a sequel hit the big screen grossing over $310 million worldwide.
The third installment will be released in August this year, starring film favourites Stallone, Jason Statham and Jet Li, who reprise their roles as leader of the titular group of mercenaries Barney Ross, second-in-command Lee Christmas and martial arts specialist Yin Yang, respectively.
Brosnan will next hit the big screen in 'A Long Way Down' opposite Breaking Bad's Aaron Paul, 'That Awkward Moment' actress Imogen Poots and Toni Collette.

Marcus Mumford is using unheard Bob Dylan lyrics for a new project.
The Mumford and Sons frontman has penned new words to unfinished tracks written by the legendary folk singer in the late sixties during his 'The Basement Tapes' period, for a new album entitled 'Lost On The River: The New Basement Tapes'.
Producer T Bone Burnett, who also worked with Elvis Costello, 59, for the project, told the LA Times newspaper: "These are not B-level Dylan lyrics. They're lyrics he just never got around to finishing."
Dylan's 1975 album 'The Basement Tapes' was mostly recorded in the basement of the The Band's Big Pink House - a home the Canadian-American rock group shared in New York - after they toured with the singer in 1966, however this time the material is being recorded at Hollywood's Capitol Studios.
T Bone added: "This is the exact opposite of 'The Basement Tapes'. We're in the best recording studio in the world, and we're not in a basement."
The producer has already recorded almost 50 tracks for the project which also includes Carolina Chocolate Drops singer Rhiannon Giddens and Dawes guitarist Taylor Goldsmith.
The whole process will be documented in a film directed by Sam Jones which will be aired on American television network Showtime.

Lily Allen would like to be "anything like" Kanye West.
The 'Hard Out Here' singer, who named her latest album 'Sheezus', a play on the rapper's 'Yeezus' record, wants to be just like the star and is trying to break the American music market.
Lily told New York radio station Z100: "I'm totally for Kanye, he's a G, he's cool, he's Yeezus, I'd like to be anything like him. (sic)"
Asked what she would say to new American fans who are just discovering her music, she quipped: "[I'd say] pleazus buy Sheezus (sic)"
The 28-year-old singer is currently visiting the US to promote her new music and has been to the likes of New York and Las Vegas and has posted photographs of her trip on Instagram, showing her relaxing in the sun and even taking a helicopter ride over the Grand Canyon.
Meanwhile, the 'Air Balloon' hitmaker previously admitted she is "terrified" she might receive a call from Kanye after paying homage to his successful record.
She said: "I'm terrified ... I thought he'd think it was a diss, but it's totally not a diss, I love Kanye I think he's brilliant.
"He speaks his mind, whether what he's saying is ridiculous or not, he honestly does believe it and I think there's a lot to be said for that in this day and age."

Britain's Prince William and Duchess Catherine reportedly missed Prince George's first crawl.
The royal couple, who recently enjoyed a romantic getaway to the Maldives, are thought to have missed out on a major milestone moment in their eight-month-old tot's formative years as he crawled for the first time while they were away.
Prince George was being looked after by his grandparents Michael and Carole Middleton at Catherine's family home in Bucklebury, Berkshire, while his parents got some much-needed rest at the five-star Cheval Blanc Randheli resort earlier this month.
A source told Us Weekly magazine: "William and Kate are excited about the many milestones ahead. George already has a tiny tooth coming in. And his cheeks are chubbier than ever!"
The couple decided to enjoy some romantic time together in the Maldives ahead of a long three-week royal visit to Australia and New Zealand next month.
The royals will be joined by their son, who'll be looked after by his new Spanish nanny, Maria Teresa Turrion Borrallo.
The 43-year-old childminder was recently employed by William, 31, and Catherine, 32, having trained at London's Norland College.

Simon Cowell says One Direction's success enticed Cheryl Cole back to 'The X Factor'.
The singer has decided to rejoin the panel of the TV talent show because she's keen to find talent to match those who appeared on the last series she appeared on in 2010, according to the reality TV mogul.
Speaking at the opening night of new 'X Factor' musical 'I Can't Sing' at the London Palladium yesterday (26.03.14), he said: "You know why she came back ... we were having a conversation at my house and we were talking about the talent we had that final year in 2010 - One Direction, Rebecca Ferguson, Cher Lloyd, Matt Cardle - we just had great people, and we just suddenly thought we want to do it all over again.
"And that was the incentive to do it because there are still great people in this country left."
Simon - who became a father for the first time in February to son Eric, with his girlfriend Lauren Silverman - also gushed about his baby boy.
He said: "It's the best thing in the world. [He's like his] dad."
Other guests who also attended the first night of 'I Can't Sing' - which is based on 'The X Factor' format and features Nigel Harman as Simon - included Amanda Holden , Louis Walsh, Union J and Carol Vorderman.
Speaking about the musical, which was written by comedian Harry Hill, Simon added: "Harry's a very twisted individual. His vision of me and our world is quite weird, but it's very, very funny."

Simon Cowell is axing the Boot Camp stage on 'The X Factor'.
The 54-year-old mogul - who is returning to the singing competition's judging panel with Cheryl Cole - is changing the show's format in order to lure back viewers and has opted to axe Boot Camp in favour of the controversial six-chair challenge which was introduced last year.
A source told The Sun newspaper: "Simon thinks the boot camp process can drag on a bit and isn't very exciting.
"The plan is to axe it and just focus more on the six-chair challenge. Simon loves it -- the drama and controversy is right up his street."
The six-chair challenge sees the judges' reward contestants with a seat - and a place in Judges' Houses - right after their performance if they are impressive enough. However, no act is safe as another singer can replace seated contestants as the callbacks continue.
The six contestants lucky enough to have seats by the end of the day go through to Judges' Houses to fight it out for a place in the Live Shows.
It's thought Simon is a fan of the drama of the challenge and thinks it makes better TV than the "tedious" Boot Camp stage, which saw around 200 contestants whittled down through various singing tasks.
The six-chair challenge came under fire for being cruel by some viewers last year, but Simon has previously championed the format change.
He said in October: "This is some of the most exciting TV we've made on one of these shows. It is dramatic, it is controversial, but we all love that. People went nuts, half loving it and half hating it."