Carey Mulligan is terrified of singing.

The 29-year-old actress showcases her vocals in the trailer for her new movie 'Far From the Madding Crowd', having previously sung in both 'Shame' and 'Inside Llewyn Davis', although she found the latter the least stressful experience because she had the help and support of Justin Timberlake.

She said ''Justin did everything he could to make me feel more at ease when I had to sing.

''He was really helpful on the set and that made it much less painful.

''I'll never be a singer, and singing still terrifies me, even though I can fake it.

''At least I was able to spend some time in the studio with Justin working with [producer] T Bone Burnett for a month, so by the time I had to sing in front of the camera it was less of an ordeal.''

Carey - who is married to Mumford & Sons frontman Marcus Mumford - found it hard singing in 'Shame' because she had to perform live.

She recalled to Psychologies magazine: ''Singing in 'Shame' was much more stressful because I had to do it in one take and the camera was directly in front of me.

''Also, the director, Steve McQueen, want to do it all live. That made it a much more emotional kind of performance, whereas in 'Llewyn', we were mimicking folk singers of the time so it was more light-hearted.

''Singing is still not my thing though. I've always been nervous singing in front of people and I don't think that's ever going to change.''