In a trailer for the upcoming musical "Nine," a beautiful go-go dancing, Beyonce-swaying blonde shows off an impressive set of pipes and some decent moves.
No, it's not Fergie, but her suprise co-star Kate Hudson. Yep, Hudson can sing. And fellow "Nine" actors Daniel Day Lewis, Nicole Kidman, Penelope Cruz and Marion Cotillard don't do such a bad job either.
It's always a surprise for audiences when actors known more for their acting than their singing break out into song on the big screen. And some surprises are more pleasant than others. Last year Meryl Streep got cheers for her performance in "Mama Mia!" Her co-star Pierce Brosnan got jeers.
The "Nine" ensemble are the latest actors to sing on the big screen. They talked about the challenge of performing in a musical on "The Oprah Winfrey Show" Wednesday.
"I was very intimidated by it," two-time Oscar winner Lewis told Winfrey. "Rob has a way of making it seem like second nature."
That would be stage-turned-screen director Rob Marshall, who won an Academy Award for directing "Chicago."
"Just to sing in the audition" was an honor for Hudson. "I felt like I'd do Rob's craft (food) service," Hudson told Winfrey. "I grew up in a dancing family. For me working with Rob Marshall was like working with (famed choreographer and director) Bob Fosse. And then to work with everybody here, it was just truly a phenomenal experience."
"It was so fun, truly maybe the best experience to date on a film for sure," Hudson added.
Most may not realize that "Nine" is not Hudson's first on-screen singing performance. She took to the mic in the 2000 film "About Adam," in which she played a torch-singing waitress.
In real life, she's also been known to burst into song. A couple years ago, she surprised patrons at a piano bar on the Italian Riviera when she sang Carole King's classic "You've Got a Friend."
However, when it came time to film her big scene singing and dancing after two months of rehearsal, Hudson choked.
"The first time I got on a stage and had to be fully on, I just froze," she said.
Luckily, she had a big supporter on set that day: her mother, actress Goldie Hawn.
"It was emotional for Mom," Hudson said. "That's how she started her career, as a dancer."
Watching Hudson shimmy and shake on screen, it's hard not to picture Hawn 40 years earlier doing similar moves on television's "Laugh In."
Winfrey also asked Hudson about her relationship with Yankee slugger Alex Rodriguez. After laughingly dodging the question of how they met (years earlier), Hudson offered, "I am very happy."
Kidman has sung before on screen, in Baz Luhrmann's "Moulin Rouge," but doesn't exactly enjoy it.
"I don't particularly like hearing myself sing," she told Winfrey. "I can't express myself exactly how I want to, because I can't hit the notes. I would have loved to sing that song in a high soprano voice, but I don't have that voice."
Cruz had to discover her singing voice. "It was very scary," she said. " I've never sung before professionally, only at home. I own a Karaoke machine. I was really terrified."
She also had challenging choreography to master, twisting and twirling ropes with stripper-like moves. "The first day I saw the choreography...I said, 'You should almost fire me. I don't know if I'll ever get there.'"
But she did, and though her nerves got the best of her on the first day she recorded her song at London's famed Abbey Road recording studio, she produced a better recording -- and the one that ended up in the film -- on the second day.
Now Cruz said she would gladly do a musical again.
Cotillard, who won an Oscar for her performance as Edith Piaf in the French film "La Vie en Rose," always dreamed of being in a muscial. "Since I was young, I would watch 'Singing in the Rain' again and again, and I got pretty good at doing the choreography," she told Winfrey.
With the recent revival of the musical on the big screen, we are likely to see even more singing actors.
In Streep's case, she actually can sing. "She always had a reputation as being able to sing," New York casting director David Vaccari told ABCNews.com. "People have said that about Glenn Close, as well. People in the industry know they can sing. But not everybody in Middle America knows it."
Brosnan, on the other hand, can't sing, but in "Mama Mia!" it didn't seem to matter. Entertainment Weekly's reviewer wrote: "And just wait until Pierce Brosnan warbles 'S.O.S.' You'll laugh. And then you'll be charmed."
"In 'Mamma Mia!' you have a couple people gamely attempting to carry a tune," Carl DiOrio, deputy film editor at The Hollywood Reporter, told ABCNews.com. "Some pull it off better than others. But I haven't seen any evidence that Brosnan's lesser abilities in that regard will serve the movie in any sort of negative way. You almost have to give him points for being gamely enough in his efforts."
"Until they surface in vehicles like these, people not necessarily known for their singing abilities are going to rise and fall in whatever the particular vehicle they choose to sing in," DiOrio added.
Reese Witherspoon and Joaquin Phoenix rose to the challenge, doing their own singing in the Johnny Cash biopic "Walk The Line." Phoenix spent months at rock and roll boot camp, strengthening his voice and learning how to play guitar, to step into Cash's boots.
"I was surprised just to get through a song!" Phoenix told CNN in 2005. "I never sang before ... so to suddenly go to John was so odd to me. ... It was very strange to have to use a part of my voice that I didn't know existed."
Shocked by his Golden Globe win, he said, "Who would ever have thought that I would win in the comedy or musical category?"
Since quitting acting, Phoenix's new career as a rapper has been soundly dismissed.
But it was Witherspoon who took home the Oscar for her portrayal of Cash's wife, singer June Carter Cash. To prepare for the role, she took six months of extensive voice lessons and learned to play the autoharp.
Of course, she also had some singing chops to start with.
"I wanted to be a Broadway kid. I wanted to be on Broadway when I was 12, so I had singing lessons, but nothing prepared me for what it's like to stand in front of a microphone and hear it played back to you," Witherspoon told the Associated Press. "It's so humbling, and it made me really appreciate people who are naturally gifted."
Phoenix and Witherspoon have raised the bar for actors singing on screen. Actors can't get by anymore with having their voices dubbed by real singers, like Natalie Wood did in the screen version of "West Side Story."
"I don't think we're going to see a Natalie Wood scenario happen too much, unless the movie is going for a very campy kind of a feel," Vaccari said. "These days, I don't think people would go for that. The publicity backlash would be worse."
In Woody Allen's 1996 musical "Everyone Says I Love You," Drew Barrymore reportedly convinced Allen that her voice was too awful for even the "realistic singing voice" concept he was going for, and was the only one dubbed in a cast that included Julia Roberts, Edward Norton and Natalie Portman.
But when she played a songwriter opposite Hugh Grant in 2007's "Music and Lyrics," she bravely sang herself.
"She was tuneful and not completely embarrassing," Ann Donahue, senior editor at Billboard magazine, told ABCNews.com. "I think if it's an endearing part of the character, it's OK if it's not perfect."
"Sometimes you sacrifice a little of the singing if all the other areas are strong," Vaccari said.
Such was the case with the decision to cast Johnny Depp in "Sweeny Todd."
"He's a great actor. Sure, there are better singers. But I don't want to see Jon Bon Jovi play that part," Vaccari said. "I don't think there are a tremendous amount of options, people who can sing and are very bankable names."
"I don't think anyone is going to put someone in a Broadway musical if they can't sing. In a movie, it's a little different," Vaccari said. "There are things you can do to make it sound better."
Then there are some actors who so enjoy singing on screen that they decide to cut an album, often to mixed reviews and success. Lindsay Lohan's debut album peaked at No. 4 on the Billboard pop chart, but her second died quickly on the vine. Her third is due out in November.
Scarlett Johansson's first album was panned by some critics, but Donahue said it had a decent showing on Billboard's Heatseeker chart, which tracks albums that appeal to the college crowd.
"Some actors secretly know they shouldn't be singing, but they like the chance to try something new," Donahue said. "It's hard to do both and have a reputable career."
Donahue said she can only think of one person who excels at both singing and acting:Jennifer Hudson.