Eddie Redmayne has been testing his live singing skills on set, ahead of filming Les Miserables later this year.
Oscar-winning director Tom Hooper wants to capture his all-star cast singing live - not miming to a soundtrack - for his version of the hit musical
"I'm in hardcore singing lessons," Redmayne told the BBC at Bafta on Wednesday.
"I was down in Pinewood yesterday doing some tests with Tom and it's all happening."
Also starring Hugh Jackman, Russell Crowe and Anne Hathaway, Les Miserables starts filming in March and will be released on 7 December.
The story, based on Victor Hugo's epic novel, sees Jackman play ex-convict Jean Valjean, hunted for decades by the policeman Javert (Crowe) after he breaks parole. Hathaway plays factory worker Fantine.
Redmayne - who starred opposite Michelle Williams in My Week With Marilyn - plays student Marius.
The 30-year-old actor said he was attracted by the "spontaneity" of singing live.
"If you record an album and then make a music video to that album you are restricted by the choices you made. It is months in advance of what you know what your character is actually going to be doing."
He added: "So the idea is that the piano will play and we'll sing live - they've tested it all and I think it will be good."
On his approach to singing the solo Empty Chairs at Empty Tables, Redmayne said: "You have to forget all the versions you've heard and deconstruct the song and try to find your own way through it. We'll have to wait and see whether it works or not."
Redmayne, currently playing Richard II at London's Donmar Warehouse, also stars in the BBC's forthcoming version of Birdsong.