20 actors who completely transformed themselves into music legends

The English actor transformed into the folk singer, Southern drawl and all, for "I Saw the Light." Hiddleston stayed with singer-songwriter Rodney Crowell for five weeks and was coached in Williams' mannerisms and singing style. The film hit theaters March 25.

Cheadle was first roped into this project back in 2006 when Miles Davis, who died in 1991, was posthumously inducted into the Rock and Roll Hall of Fame. Afterward, Davis' nephew said Cheadles would play his uncle in a film of his life. Cheadle eventually cowrote a script, signed on to direct, and portrayed the jazz musician in "Miles Ahead," which will be released April 6.

(Cheadle also portrayed Sammy Davis Jr. in 1998's “The Rat Pack,” for which he won a Golden Globe.)

Jason Mitchell's transformation into the late N.W.A rapper Eazy-E for "Straight Outta Compton" blew critics away. The relatively unknown "consistently out-acts the rest of the performers," a New York Times review said. Mitchell, who has a similarly built frame to Eazy-E, gained weight, practiced a South Los Angeles accent, and learned how to rap for the role, according to the Los Angeles Times. Corey Hawkins became Dr. Dre and O'Shea Jackson Jr. transformed into his father, Ice Cube, for the film.

To play a younger version of the Beach Boys founder Brian Wilson in "Love & Mercy," Dano learned how to play piano and bass. Wilson told the Chicago Tribune, "He looked a little bit like me at age 24. But the way he portrayed me producing records — you know? — was very factual, accurate, stimulating." Dano received a Golden Globe nomination for best supporting actor. John Cusack plays an older Wilson in the film.

Saldana transformed herself, though not necessarily for good, as many see it. The actress plays Nina Simone in an upcoming biopic, set for an April 22 release, in what has been a controversial choice. Her skin has been darkened and the filmmakers added prosthetics to make Saldana appear more like Simone. In response to the casting choice and backlash, Simone's daughter told Time, “It’s unfortunate that Zoe Saldana is being attacked so viciously when she is someone who is part of a larger picture. It’s clear she brought her best to this project, but unfortunately she’s being attacked when she’s not responsible for any of the writing or the lies.”

Portraying the "Empress of Blues" "left this mark on me," Queen Latitah told NPR. The singer was praised for her role in the HBO film "Bessie," which won an Emmy for outstanding television movie.

Boseman channeled his inner funk and broke it down as James Brown in 2014's "Get on Up." The actor spent three hours in the makeup chair for his full-body prosthetics and wig to get the looks. And with the help of a vocal coach and choreographer and advice from some of Brown’s surviving relatives, as well as Mick Jagger, one of the film's producers, Boseman gave an electrifying performance.

The life of Frankie Valli and the Four Seasons has been documented on Broadway since 2005, and John Lloyd Young, who originated the role on Broadway, reprised his role in Clint Eastwood's "Jersey Boys."

Woolard's first role was portraying Biggie Smalls in 2009's "Notorious."He is set to reprise the role of The Notorious B.I.G. in "All Eyez on Me," an upcoming biopic about Tupac Shakur.

Cotillard received critical acclaim for her portrayal of French singing icon Édith Piaf and won numerous awards, including the Oscar for best actress. She wasn't initially considered for the role, but when she met with director Olivier Dahan, he was transfixed by her eyes and how they reminded him of a photo of a teenage Piaf.

Phoenix earned an Academy Award nomination for best actor for his portrayal of the beloved country musician. He sang all of the songs in the film, mimicking Cash's signature voice.

Foxx received universal acclaim for his portrayal of the blues legend Ray Charles, for which he won the Academy Award, Golden Globe, BAFTA Award, Screen Actors Guild Award, and Critics' Choice Award for best actor. To embody the blind pianist, he had to lose nearly 30 pounds and had his eyes glued shut every day.

Lopez's breakout role came when she was cast as the beloved Tejano singer Selena, but the Puerto Rican actress was met with some backlash because of her heritage. Lopez perfected the slain singer's dialect and studied performance footage of the pop sensation. ”This is someone who’s fresh in the public’s mind, so you need to do your homework on this gig,” Lopez told Entertainment Weekly.

Bassett nailed the strong-willed Tina Turner and earned an Academy Award best actress nomination and won a Golden Globe for "What's Love Got to Do With It." Bassett prepared for her audition with the film's choreographer, and after performing "Proud Mary," she got the role. Laurence Fishburne, who played Ike Turner, also earned an Oscar nomination.

To land the role of The Doors rocker Jim Morrison, Kilmer made his own eight-minute video highlighting his singing abilities and changing his looks to match Morrison to send to director Oliver Stone for "The Doors." Once cast, he dieted for months and spent six months rehearsing songs. He also trained with Paul Rothchild, who produced all but one of The Doors' albums. Surviving band members were not thrilled with the film.

Lange received high praise for her transformative performance as Patsy Cline in "Sweet Dreams." She earned her fourth Oscar nomination for the role. Meryl Streep wanted to play Cline, but later said, "When I saw ['Sweet Dreams'] ... I couldn't imagine doing it as well or even coming close to what Jessica did because she was so amazing in it."

Quaid studied piano 12 hours a day for six months in order to learn how to imitate Jerry Lee Lewis' piano skills. Though Lewis wasn't a big fan of the film "Great Balls of Fire!" according to AMC, Lewis said Quaid "really pulled it off."

Spacek earned an Academy Award for her portrayal of country singer Loretta Lynn in "Coal Miner's Daughter." Lynn had chosen Spacek to play her based on a photo she saw of the actress. To prepare for the role, Spacek traveled with Lynn for a year to study how she spoke and sang. Spacek did all her own singing in the movie.

Busey scored his first and only Oscar nomination for his portrayal of Buddy Holly in 1978's "The Buddy Holly Story." He played the guitar and recorded the songs for the film, as well as lost 32 pounds to play Holly, according to Busey's biography.

Mantegna played Dean Martin in the TV film "The Rat Pack," earning a Golden Globe and Emmy nomination for his role. About playing the role, Mantegna has said, "My goal wasn’t to mimic him. It was to capture him."