In June, "Transformers" actor Shia LaBeouf caused a stir by appearing nude in a music video for Icelandic folk band Sigur Ros. In the same week, "Harry Potter" actor Daniel Radcliffe played a drunk in a Slow Club video, and in March, "Prince of Persia" star Jake Gyllenhaal turned homicidal for The Shoes.

Well-known actors appearing in music videos goes back to the early days of MTV with Vincent Price in Michael Jackson's "Thriller," but that was when music videos attracted millions to television. Now, YouTube and other video websites are capturing the eyeballs, offering creative outlets for stars and building reputations for cutting-edge bands.

"Short of doing a feature film, this is a way (for actors) to work with directors, and perhaps make an impression on them for a lengthier professional collaboration," Keith Caulfield, Billboard magazine's associate director of charts, told Reuters.

For LaBeouf and Sigur Ros, the collaboration came about through director Alma Har'el, one of 12 filmmakers selected by the band to create videos for tracks off their album "Valtari."

The video shows LaBeouf, 26, in a dysfunctional relationship with a woman and includes violence, drug use and nudity. It has amassed more than 2 million views since its June 18 release.

"Harry Potter" actor Daniel Radcliffe also made headlines playing a tormented drunk for British indie band Slow Club's music video "The Beginners," a topic that may have deeper meaning for the actor, who in February revealed his own struggles with alcohol to British magazine Heat.

Slow Club singer Rebecca Taylor told Reuters the actor worked closely with the video's director, and she called his performance "arresting."

"We were all anxious to make it a good video, a good performance and something that enhances the song. We didn't want having somebody as high profile as Daniel to just be the concept," Taylor said.

Both Radcliffe and LaBeouf were unavailable for comment, but Gyllenhaal did reply in an e-mail about his involvement in the video for "Time to Dance" from French indie band The Shoes.

"I did the video because it exists alone, by itself. Like a question mark at the end of a sentence," Gyllenhaal wrote.

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In the video, directed by British filmmaker Daniel Wolfe, Gyllenhaal, 31, plays a homicidal fencer who stabs and beats people to death. The Shoes dreamed up the concept with Wolfe, who then called in Gyllenhaal.

"We needed a great actor to do it as we didn't want (gratuitous) violence in our video. We wanted this as a piece of art and not a buzz video," band member Guillame Briere told Reuters.

Briere said that for Gyllenhaal, the video was a "really different experience from what he is doing normally" and a chance for him to show people "how good he is" as an actor.

In the past, celebrity cameo appearances in videos were mainly reserved for established music artists who could rope in high-profile actors and directors for big-budget videos that, in turn, were expected to boost album sales.

Eddie Murphy played a pharaoh in Michael Jackson's "Remember The Time," Christopher Walken danced in Fatboy Slim's "Weapon of Choice," and "Clueless" actress Alicia Silverstone became a household name after starring in three Aerosmith videos.

But even on MTV, the format is no longer as relevant as it once was, and YouTube and other websites are offering artists a vast platform to reach fans, leading to a resurgence of music videos online from the likes of Lady Gaga and Justin Bieber.

"Videos could be arguably more influential now because anyone can see them at any time, but the problem is getting that video in front of someone that wouldn't have normally watched it," said Caulfield.

While harnessing Hollywood star power is one proven way for indie bands to get videos seen, the collaborations don't always translate to high record sales over long periods of time.

The Shoes' "Time To Dance" has sold 2,000 downloads in the United States since its release in March, according to Nielsen SoundScan, but roughly one-half of those came in the week the video was released.

For Slow Club, working with Radcliffe has boosted the reach of the "Beginners" video, amassing more than 347,000 views since June 19, but the band isn't banking on it for long-term success.

"It's been great to reach more people. It always is. But it's not like we sat around drinking Moet and feeling like we've 'made it' now," said Taylor. "We are pretty laid back about where we are and where we reach."

(Reporting By Piya Sinha-Roy; Editing by Bob Tourtellotte and Eric Beech)

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