Amanda Seyfried's biggest 'Les Miserables' challenge was ''singing live on camera''.

The 27-year-old star appeared in the musical adaptation as Cosette, and she admitted her experience in hit musical 'Mamma Mia!' didn't necessarily prepare her well for this project, which saw cast members ''singing live'' instead of pre-recording their vocals.

Speaking to the Mail on Sunday newspaper's You Magazine she said: ''[My biggest challenge was] singing live on camera.

''It was such a different style from the songs I did in 'Mamma Mia!' and a lot of people, including me, were scared I wouldn't have the stamina for it. But I worked really hard with my voice coach.''

The film also stirred up memories of the actress' biggest regret, when she quit learning opera-singing as a teenager.

She revealed: ''[My biggest regret is] quitting opera singing training when I was 17 - that had been my passion before acting took over and I wish I had stuck with it.''

As well as wishing she had kept going with the lessons, Amanda also admitted she wants to let loose and become ''less controlling'' as a person.

Asked how she would change herself, she added: ''I would be less controlling. I could use some spontaneity in my life - I'd also like to be less scatterbrained.''