The idea of brooding, dramatic double-Oscar winner Daniel Day-Lewis singing and leaping around a stage in a movie musical seemed as improbable to him initially as it might be for audiences.

But the British actor, famed for immersing himself in intense roles such as oil baron Daniel Plainview in There Will Be Blood, eventually shrugged off worries about holding a note in new musical Nine -- an homage to influential Italian film director Federico Fellini -- which begins its run in U.S. theaters on Friday.

It was puny, it was bloody puny, Day-Lewis told Reuters of his voice when he auditioned for director Rob Marshall.

He (Rob) thought it could be something, I thought he couldn't possibly know that from what he had heard.

Surrounded by a plethora of female stars from Sophia Loren to Penelope Cruz, Day-Lewis adopts a thick Italian accent to play the central role of film director Guido Contini in Nine, which first played as a stage musical on Broadway in 1982.

The movie opens in New York and Los Angeles on December 18 and across the United States on December 25, and this week earned five Golden Globe nominations, including one for best actor in a musical or comedy for Day-Lewis.

Nine is based on Fellini's classic autobiographical 1963 film 8 1/2 that follows the director's struggle to unblock his creativity after making what he estimated to be eight and one-half movies. Fellini died in 1993.

One of the most anticipated films of Hollywood's holiday season, Nine also features Oscar winners Nicole Kidman, Judi Dench and France's Marion Cotillard, along with Kate Hudson and Black Eyes Peas singer Fergie. They play muses for the tortured director and inspire realizations about his career and life.

Unlike his female co-stars, Day-Lewis manages to avoid much dancing in the movie, but he said most of the cast had qualms similar to his about their singing skills.

We all shared the same doubts. We are not professional singers or any kind of amateur singers, apart from Fergie, so I think we all wondered whether we would be able to achieve the standard, he said.

FELLINI'S ENORMOUS SHADOW

The 52 year-old actor said he had long felt a connection to Fellini, which meant he had to fool himself into forgetting that the film was inspired by the man considered one of the greatest directors of all time.

It is an enormous shadow that he casts which you might never emerge from if you allowed it to intimidate you too much, he said. We couldn't embark on this -- I couldn't have -- if I thought we were some way connected to '8 1/2'. I just completely denied that fact.

The movie was co-written by Anthony Minghella (The English Patient) and was his final work before he died last year.

But the main credit for the film belongs to Marshall, who directed 2002 best picture Oscar winner Chicago, an adaptation of the stage musical. His first casting choice was Sophia Loren -- the only Italian in the film set in Italy.

We were all doing something that was far-reaching and there was fear every day from all of us, Marshall told reporters. He said the whole cast rehearsed for six weeks before shooting and the set was devoid of egos.

The support that I saw happen amongst the company was extraordinary, he added, recalling as an example Day-Lewis turning up one day to watch Cruz rehearse. Daniel was there saying 'You are a warrior, keep going!'

Other cast members said Day-Lewis, who is known for staying in character off set during filming, was inspiring in his commitment to the role.

In his mind is a constant thought about what he has to do next, Loren said. He was very intimidating because he was somebody that was not reachable sometimes and then at the same time he was with you all the time. He is very strange -- and I love him a lot.

Day-Lewis said he found a connection with his character who questions whether his inspiration has run out.

I don't work that often so I am able to work with the same degree of compulsion and vigor that I always did, he said. But I have no doubt that if I went into a period of working without a real appetite, I would very soon arrive at that place that Guido has at the beginning of the story.

And in the end, he said, he realized the acting was as important as the singing.

I mean, can I sing a song? Everyone can sing, we all can sing, he said. But it's about finding that strange line, that invisible line between speech and song.