Dwayne Johnson wore a beard made of testicle hair for 'Hercules'.
The 42-year-old star - also known by his wrestling name "The Rock" - stars as the Greek hero in the upcoming film of the same name and he's confessed he was shocked to find out what parts of his costume had been made out of.
Speaking on 'Live! with Kelly and Michael', he said: "The beard hair, I've got to mention this, this is crazy. The beard wasn't lace so it had to be put on strips cut in tri, quarter inch wide, piece-by-piece.
"So I asked my Italian designer, 'Matteo what is this?' And he goes, 'Oh, it's the hair from a yak'. It's very expensive and very fine hair and I said, 'Yak?' And he says, 'Yes, yak'. And he's putting it on my face like this [rubs the area around his mouth] and I say, 'What part?' And he goes, 'The testicles'.
"It's the commitment of which I will go to."
The 'Pain & Gain' actor - whose usual hairstyle is that of a shaved head - has long flowing locks in the movie and he's revealed it took nearly four hours to put the wig on every day on set.
He explained: "It's a system, it's a process, it's an experience. Everyday for five months. Every day, three and a half hours, every day.
"Three and a half hours every morning. So I would get up at half three and then I would eat and train again, as I had to train twice a day for the role, and then I would go and sit in hair and make up for three and a half hours for the transformation."

Katie Price launched an expletive-filled rant at two of her former friends on Twitter for having affairs with her husband.
The former glamour model branded Chrissy Thomas a 's**t' and Jane Pountney a 'w***e' on the micro-blogging site, even though she has insisted she is planning to work things out with Kieran Hayler, who is being treated for sex addiction.
She wrote: "hope WALLS ice cream keep eye on Chrissy s**t thomas she is also shagging a married worker whom got married within past year and has I child
"When Chrissy s**t thomas drove up in lorry to Scotland with him few months ago they stayed night had sex all night
"There is a lot about Chrissy s**t thomas media would love to know about 😉 with celeb married men
"I hope anyone who still wants to be friends with jane w***e pountney now realises she is not loyal who will open her legs 2 ur husbands. (sic)"
Katie, 36, then calmly ended her rant by writing: "That's me done for the night ! TV time tea and biscuits with my family , have good evening everyone x."
This comes just after Katie - who is pregnant with her fifth child, her second with Kieran - that she and her spouse are working on their relationship following her discovery that he had cheated on her but she will never forgive her former pals.
She said: "They are wicked witches, the pair of them. They are just prostitutes in my eyes and I hope they suffer for the rest of their lives the same way they're making me suffer. This proves they are not capable of being loyal to anyone."

Natalie Imbruglia is considering joining Tinder.
The 39-year-old actress-turned-singer has admitted that her lack of success in her love life has led her to seriously think about signing up for the cult dating app, which lets users initially simply judge each other based on appearance.
Speaking on Kiis FM's Kyle and Jackie O show, she revealed her relationship status is "Shocking! I'm so single", before adding, "I'm starting to consider that I should go on Tinder... Well where am I going to meet people?"
The 'Torn' hitmaker is particularly keen to join after one of her friends found love through the app.
Admitting her reasons for joining, she said: "My girlfriend in London has fallen madly in love on her third Tinder date - and I'm incredibly jealous.
"He's a really nice normal guy, a director... I've met him he's really sweet and really normal.
"Everyone I know whose single in London is on Tinder."
However, the radio presenters were not impressed, with Jackie O commenting: "Tinder that's... I dunno if you'd be right for Tinder."
To which Natalie replied: "Is it different here? Is it dodgy here? Should I not be talking about it."
Natalie was previously married to Silverchair frontman Daniel Johns in 2003 before the couple divorced in 2008.
She has also been linked to a string of famous men including David Schwimmer and Harry Styles.

Olly Murs has been named Rear of the Year.
The 'Hand on Heart' singer - who shot to fame as runner up on 'The X Factor' in 2010 - beat tennis player Andy Murray into second place for the coveted best butt prize and was thrilled to pick up the accolade.
He tweeted: "Thanks to everyone that voted for my arse we are both very proud of this award"
Olly even changed his profile photo to a picture of his pert behind as a tribute to his new status.
In the female category, former 'Countdown' mathematician Carol Vorderman was victorious yet again, making her the first celebrity to win the award twice.
The 53-year-old TV presenter previously won Rear of the Year in 2011 alongside 'Strictly Come Dancing' professional Anton Du Beke and this year beat 'X Factor' judge Cheryl Cole to the top spot.
Like Olly, Carol shared the news via Twitter. She joked: "So Big Bum here has won THAT award for a second time.... one for each cheek, so to speak...it's a strange world!!! (sic)"
She also joked in a statement: "As I said when I won it in 2011, I always suspected there were a lot of people out there who were glad to see the back of me. It now appears there were even more than I thought."
The lighthearted competition first started in 1976 and named 'EastEnders' actress Barbara Windsor as the winner.
Since then, Rear of the Year has given trophies to plenty of perky-bottomed celebrities, including Rachel Stevens, Charlotte Church and Ian Wright.

Demi Lovato had to break her strict diet so she didn't offend US President Barack Obama.
The 'Skyscraper' hitmaker usually sticks to a raw food, gluten-free eating regime because of allergies to wheat and dairy, but didn't want to offend host Robert Rodriguez or his special guest at a party at the filmmaker's Texan home last month.
She told 'Extra': "I try to eat raw food whenever possible. I don't eat it all the time just because I'm the type of person that if I do something, if I go all one way, I get burnt out...
"I'm gluten-free and dairy-free because I'm allergic to them. I just eat vegan and raw as much as possible and it's really changed my body and made me feel better.
"But you kind of can't turn down pizza that Robert Rodriguez handmade - and that you are also eating with the president."
Demi also admitted she was left embarrassed by her chat with the commander-in-chief that night - but ended the conversation bursting with pride thanks to his kind words.
She explained: "I reminded him that we'd met before. I sang at Christmas in Washington. He said, 'I know who you are. You're a mega-star, you think I'm stupid?' I was like, 'No Mr. President, I'm so sorry, you're not stupid!'
"Then we did talk about his daughters and [his wife] Michelle, and he was like, 'You just scored me cool points,' and I said, 'You scored me cool points! Thanks for calling me a mega-star."

Zoe Saldana is "about" three months pregnant.
The 'Guardians of the Galaxy' actress - who has been the subject of rumours in recent weeks that she is expecting her first child - and husband Marco Perego are delighted about becoming parents, but don't intend to confirm the news just yet.
A source told Us Weekly magazine: "Zoe is about three months pregnant. But she will only announce the news when she's ready.
"Zoe has always wanted a big family, and Marco's on board too!"
The 36-year-old beauty - who was in a relationship with entrepreneur Keith Britton for 11 years until November 2011 and later dated actor Bradley Cooper until January 2013 - previously admitted she was in a "beautiful place" in her life when she met Marco last year and was ready to marry him shortly afterwards as she finally felt comfortable with herself.
She recently said: "I was finally able to spend time without being in a relationship and even though, it was a short period of time, it was beautiful.
"Where I lost that fear of being alone. It was bliss.
"I met my partner when I was in really a beautiful place in my life. When you are desired and you desire, so many things in your life start to make sense."

Naya Rivera has married Ryan Dorsey following a whirlwind romance.
Although the 27-year-old 'Glee' star only split from rapper fiance Big Sean in April, she and longtime friend Ryan tied the knot on July 19 in Cabo San Lucas, Mexico, in front of a small group of friends and family.
They told People magazine: "We feel truly blessed to be joined as husband and wife. Our special day was fated and everything we could have ever asked for.
"True love always prevails."
The wedding comes as even more of a shock as it was only revealed last week that the couple were dating, when they were spotted on vacation together in Mexico.
However, they have been friends for four years after meeting when actor Ryan moved to Los Angeles.
Naya wore a lace Monique Lhuillier gown for her big day while her new husband was kitted out in a Dolce & Gabbana suit.
People reports the actress "carried a bouquet of daisies and baby's breath and the couple exchanged Neil Lane rings".
Big Sean called off his engagement to Naya in April, six months after they started dating.
A representative for Big Sean said at the time: "After careful thought and much consideration, Sean has made the difficult decision to call the wedding off ... Sean wishes Naya nothing but the best and it is still his hope that they can continue to work through their issues privately. We will not be commenting again on this matter."

Taylor Swift looked like a star as she stepped out in a mint green summer dress with pink heels before meeting pals for lunch in New York City's East Village.

Rachel McAdams wore a beautiful one-shouldered dress as she celebrated the premiere of her new movie, 'A Most Wanted Man', at New York City's Skylark cocktail bar.

Anne Hathaway dressed in a mint green maxi dress and sleeveless denim jacket as she ran errands in the SoHo district of New York City.

Kate Hudson looked stylish in a white vest and black calf-length skirt as she left her hotel in New York to make her way to the 'Late Night with Seth Meyers' show.

Miranda Kerr looked radiant as she showed off her toned tum in a black crop top and grey leggings as she arrived at her New York home with her hair tied back into a low bun.