Demi Lovato is backing a campaign to support equal marriage rights.
The 21-year-old singer-and-actress - who is an avid supporter of equality for the LGBT community - has asked Americans to "stand up for what's right" and end discrimination of same-sex couples.
In an e-mail sent out by the 'Americans for Marriage Equality' campaign, Demi wrote: "My generation knows that it's wrong to tell two people in love they can't get married, simply because of who they love.
"We've got to stand up for what's right and let our voices be heard if we want to put an end to marriage discrimination. The America I know and love values everyone, and that includes the LGBT community."
The 'Warrior' singer also recorded a video to support the campaign, in which she said allowing same sex couples to marry would "strengthen the institution of marriage".
Demi said: "I believe that love comes in all different shapes, sizes and colours. So whether you're LGBT or straight, your love is valid, beautiful and an incredible gift.
"So let's protect them and strengthen the institution of marriage by allowing loving, caring and committed same sex couples to legally marry."
In America, 31 states still do not allow couples of the same sex to marry.
Demi - whose new track 'Really Don't Care' was filmed at Los Angeles Pride - asked the public to back the campaign via an online petition.

Britain's Queen Elizabeth was given a selection of knitwear for Prince George today (10.07.14).
The monarch and her husband Prince Philip were presented with tiny woolly clothing for their baby grandson as they arrived at the historic John Smedley factory in Lea Mills, Derbyshire.
Designer Jacqueline Turner gave the Queen several Rhino polo shirts and Aardvark sweaters as a present for the 11-month-old tot, as well as a gift for herself and Philip upon their visit to the brand's HQ, which is celebrating its 230th anniversary this year.
Jacqueline said: "I feel very honoured. I explained that the gifts were for Prince George. The Queen looked very happy when I told her the items were named after animals.
"The Queen was presented with an item which she regularly purchases from us while the Duke looked very pleased with his gift."
The royal couple were given a history of John Smedley and shown how the clothing is made, and the queen appeared to be fascinated with some of the machinery used.
They were then treated to a catwalk event showcasing the brand's spring/summer 2015 collection.

A Keith Urban hologram has been unveiled in Sydney.
The computer-generated likeness of the singer performed in the city's Pitt Street Mall today (10.07.14), and fans were able to interact with it and even have their own jam session with the 46-year-old star.
The hologram - which was created using the same technology that saw a virtual Michael Jackson perform at the Grammy awards earlier this year - kicked off the day by addressing the crowd.
Virtual Keith said: "Thank you, thank you. Alright I'm going to play for you first, and then a little bit later we'll try something very cool.
" ... Alright this first one is called 'Somewhere In My Car'."
He then performed his new single, before fans were given the chance to "chill or rock" with him, with the audience given a choice of instruments including guitar, harmonica, tambourine or drums.
Sammy Vincent, 33, from Hurstville, was one of the first to perform with the hologram.
He told Australia's Daily Telegraph newspaper: "It's always exciting, it was nerve-racking. It's a great way to interact.
"I'm a massive fan of him."
Sammy - who could only see the hologram on screens - said it was a "weird and wacky way" to interact with the 'American Idol' judge.
He added: "But its most enjoyable really."
The Keith Urban experience was part of a partnership between the musician and ANZ bank to promote their latest app Grow by ANZ.

The Libertines will release a new album next year.
The 'I Get Along' rockers insist there must be more to their reunion than performing gigs as they worry that will result in arguments, but need to find the time to write new music.
Carl Barat told NME magazine: "Next year. It has to be. I don't wanna just go on the road because then you'll get cabin fever and have an epic fallout.
"So yeah, I want to keep something fresh coming in. We just need to find the time [to write and record]. But yeah, it's always been the plan."
Co-frontman Pete Doherty hopes he and Carl can retreat to Europe in a similar manner to how they worked on ideas for their second self-titled album in 2004.
He said: "For some reason in my head, I'm thinking October, November time. That's what will have to happen.
"Basically it'll have to be like Paris, but in Hamburg and for a bit longer. I'm well up for it."
The band briefly reunited in 2010 for a handful of shows, but Carl felt there was more "pressure" and too many people around that time to really feel settled.
He said: "The thing with 2010 was that we had a f***ing film crew there - everything had to be done for a purpose.
"When it was the two of us [Pete and I] in Barcelona, we could literally walk and talk, take in the sights and be calm.
"And suddenly we remembered where it all came from and what it was about. We tapped back into the same place.
"We didn't to that so much last time. There was more pressure, people playing up to the cameras, but this time it was really important. I wanted to make an effort to go and see Peter."

Haim's parents set up their collaboration with A$AP Ferg.
The trio - made up of sisters Este, Alana and Danielle Haim - have teamed up with the rapper on a rework of their track 'My Song 5', and it came about after he met their mother and father at Coachella Festival in California.
Alana told the Daily Star newspaper: "Our parents met him at Coachella Festival. We played the same stage and shared a dressing room.
"Now it's a total love affair. I think Ferg loves our parents more than us."
The family trio have spoken about their parents in the past, with Alana crediting them with inspiring them to get into music when they were younger.
She previously said: "We owe our parents everything, they introduced us to music, gave us our first instruments and wanted us to become a band.
"So I always call my parents to let us know I'm still alive and OK on the road. I miss them lots, I do - it's so dorky to say it but I really do. There's times when you just miss your mom."

'Hollyoaks' will unmask Fraser Black's killer on Snapchat.
The Chester soap is set to finally reveal who murdered the gangster - who was played by Jesse Birdsall - but hours before their identity is unveiled on screen, followers of the HelloHollyoaks profile will be given a series of clues, messages, pictures and spoilers as to whodunnit.
Victoria Lutas, senior content producer for producers Lime Pictures told Broadcast: "We wanted to build a buzz ahead of the episode and, among the younger demographic who follow us on Snapchat, it is really important to be the first to know."
Soap bosses believe unmasking the killer in this way is a good reward for loyal fans.
Victoria added: "You must have a reason to launch on these platforms and then talk to the audience in an appropriate voice.
"There is so much choice for people that it is important to instil loyalty in fans of the show and make them feel valued."
Since its launch in February, the HelloHollyoaks Snapchat profile has amassed over 100,000 followers.
In the frame for Fraser's murder are his daughter Grace Black (Tamara Wall), former protegee Trevor Royle (Greg Wood), stepsons Freddie Roscoe (Charlie Clapham) and Joe Roscoe (Ayden Callaghan) and ex-employee Ste Hay (Kieran Richardson).

Verity Rushworth says Donna Windsor's crime involvement "gets really deep".
The 'Emmerdale' actress is currently embroiled in an emotional storyline after her character - suffering from cancer - has been seen teaming up with Ross Barton (Michael Parr) for various schemes, but this is only the beginning.
Speaking on 'Lorraine' today (10.07.14), she said: "It's action-packed and the stakes get really high, and this is the tip of the iceberg for her.
"The crime gets really deep and we get into sticky waters. The cancer is one element, and then there is a whole load of other things on top of that. It's going to be good."
Donna is due to tell her ex-husband Marlon Dingle (played by Mark Charnock) about her illness tonight, and Verity admitted the situation must be "absolutely horrific" for those having to go through it in real life.
She added: "he doesn't want to be seen as a victim and as soon as everybody knows, it's going to break Marlon's heart.
"How do you tell a 5-year old girl that her mum is going to die of cancer? I just can't imagine the people that have to go through that. It's absolutely horrific.
"I think she wants to grasp onto happiness for as long as she can, while she can."

Ant and Dec thought their careers were dead after 'Byker Grove'.
The TV duo admitted being dropped from the children's TV show in 1993 after four years was a definite "low" - but it ended up being an opportunity to push themselves further than they imagined at the time.
Asked what their lowest point was, Declan Donnelly told Digital Spy: "Probably the low, and we didn't know at the time it was happening for a reason, was when we got told we were leaving 'Byker Grove'.
"We were 18 and we were told that we would be too old to be hanging about a youth club. We were told that the only 18-year-olds who hang around youth clubs are pretty weird.
"As far as we were concerned, it was all over. We thought we were on the scrapheap at 18 and we were going back to college. Obviously, in the end it worked out alright."
The stars went on to have hugely a successful career together, and claimed the pinnacle was 'Saturday Night Takeaway' winning two prizes at the British Academy Television Awards earlier this year.
The show picked up the gongs for both Best Entertainment Programme and Best Entertainment Performance - and it marked their 25th year as a TV partnership in a fitting way.
Dec said: "Because it's been 25 years, it felt extra special."
Ant McPartlin added: "And because it was for 'Saturday Night Takeaway' and we'd been away and rested it for four years, to bring it back and get it nominated and win was really special. It was a really special year."

Eamonn Holmes has an "unhealthy obsession" with Ruth Langsford.
The 'This Morning' host is the "jealous" type when it comes to his wife - who presents the show alongside him every Friday - and admitted she "fascinates" him.
According to the Daily Star newspaper, he said: "I have this unhealthy obsession with Ruth, and I love being around her.
"I actually get quite jealous when anyone is taking her time away from me.
"When I'm alone with her and I have her totally to myself, there is no-one else I want to be with. She fascinates me."
Indeed, the 54-year-old star is still madly in love with his wife of four years and still finds himself thinking about how lucky he is when the they are on the air together.
Asked whether their partnership reaffirms their romance, he recently told new! magazine: "Yes and sometimes it's nice to sit back during an interview, while chats are going on back and forth between Ruth and the guest, and I'll think, 'She's gorgeous and she's my wife - I'm married to her!' "

Guillermo Del Toro is planning to make a "really bizarre" movie.
The 49-year-old director is looking to fit in the time to make a "strange little" film in between completing his haunted house horror 'Crimson Peak' and starting work on the 'Pacific Rim' sequel.
He told Collider: "Right away, in February / March I should start on another very small movie, black and white, really, really bizarre.
"We start pre-production on Pacific Rim 2 in August, and then I interrupt it briefly to go into the first of next year to do this strange little movie, and then I restart it and go all the way until we start shooting at the end of 2015 for release in 2017."
While he refused to give away much other than the project will have "one great creature", Del Toro is already eyeing a cast for the mystery movie.
He said: "It's a very small cast. I would love to have John Hurt, and there's an actress that I have in mind that is not well known but I've seen her in a short film. That's all she's really done, one feature and one short, but she has an incredibly interesting taste and I'm gonna try her out for the main role."

Mark Ruffalo claims his singing has put women off dating him.
The actor stars opposite Keira Knightley in new romantic comedy 'Begin Again', set in New York City's musical scene, but won't be showing off his own vocal skills on camera any time soon.
The '13 Going on 30' star admits his phobia stems from the time he went on a disastrous date with a girl who dumped him after hearing his strange "dork" singing.
He told London Live: "I was having a date with a girl and I thought it was going very well so I put on some music, The Police, and she was liking that and I started to sing along. And then I realised she was just staring at me.
"Then just out of her mouth came, 'You're... such a dork'. I don't think she realised she'd said that but that was the last time I ever went out with her."
Mark also revealed he attempted to sing in the movie, but it was axed by producers for everyone's sake.
He revealed: "I did sing in the movie but it was cut out. I think it might have been that bad. And I'm terrible at karaoke. I don't like it. It's not a pleasant experience for me. Or the audience."
London Go, every weekday at 6.30pm on London Live - Freeview 8, YouView 8, Sky 117 and Virgin 159.

Rebecca Ferguson has been cast as the female lead in 'Mission: Impossible 5'.
The 30-year-old actress - who received a Golden Globe nomination for her debut in the title role of BBC drama 'The White Queen' - has signed up to play the female lead opposite Tom Cruise in the upcoming action sequel, Deadline reports.
Cruise will reprise his role as secret agent Ethan Hunt while Alec Baldwin is rumoured to be in talks with Paramount Pictures to play the head of the CIA and details of Ferguson's character so far remain unknown.
Chris McQuarrie - who directed Cruise in 2012 film 'Jack Reacher' - will helm the project, which marks the fifth instalment in the action franchise, following on from 2011's 'Mission: Impossible - Ghost Protocol'.
Cruise will also produce alongside 'Star Wars: Episode VII' director J.J. Abrams and Bryan Burk while David Ellison, Dana Goldberg and Don Granger are to executive produce.
Swedish up-and-coming actress Ferguson will next appear in the Brett Ratner-directed 'Hercules' with Dwayne "The Rock" Johnson, Ian McShane and Irina Shayk.
Although details of the 'Mission: Impossible 5' plot currently remain under wraps, the film is scheduled for release on December 26 2015.