Lily James finds getting ready ''stressful''.

The 'Cinderella' star has confessed she is still getting used to donning designer outfits on the red carpet as she feels most comfortable in jeans and her boyfriend, Matt Smith's sweaters.

She said: ''When the cameras are off I'm basically in jeans and my boyfriend's jumpers. That's it - jeans and jumpers.

''I do find the make-up and the hair and the getting ready all quite stressful because it's so far removed from how I am when I'm off duty.''

The blonde beauty, 25, credits her stylist for helping her to achieve her flawless look and always has ''complete faith'' in her outfit choices.

She told Vogue magazine: ''For the red carpet I have an amazing stylist and I go to her living room and these amazing gowns are spilling out of the windows, so that's the side of it I've got complete faith in.''

Lily - who has starred in 'Downton Abbey' and will next appear in the TV mini-series 'War and Peace' - is hoping to follow in the footsteps of fellow Brit Keira Knightley as she admires her ''down-to-earth'' nature and ''bold'' career moves.

She said: ''I think Keira Knightley is amazing and I've heard also that she is one of the coolest, most down-to-earth, brilliant girls and I really look up to her in that respect. She's got it all really and I think she's made interesting bold choices in her work.''