Rising star: Kelly Reilly

'I don't know what that's all about,' muses Kelly Reilly.

'That' is the fact that after eight years of critical praise for her work in television and theatre, the refreshingly down-to-earth redhead is being touted as a hot newcomer.

It's true that her public profile has not been particularly high. However, Peaches, in which she puts Matthew Rhys's commitment-shy slacker into a spin by revealing she has a crush on him, should help to change that. If it doesn't, her performance as Helen Mirren's younger self in the hotly anticipated Graham Swift adaptation, Last Orders, certainly will. ('She's the dog's bollocks,' says Reilly admiringly of Mirren.)

Pleasantly free of that confidence-bordering-on-arrogance that drama school might have filled her with (had she been able to afford to go), Reilly admits, 'This is the first year I can believe I am an actress, rather than winging it. People tell you you're doing it, but you still feel you're going to be rumbled at any minute. You have to get your grounding yourself.'

Reilly's first big break was Prime Suspect, which brought her to the attention of playwright Terry Johnson, who cast her in his homage to Watford, Elton John's Glasses, launching a stage career that includes playing Elaine to Rhys's Benjamin in The Graduate. On television she appeared in a string of costume dramas. And then Peaches came along. 'Finally,' laughs Reilly, 'I could get out of the corset and put a pair of jeans on.'

Reilly consciously seeks out roles that demand new things from her. She is not driven by a lust for fame, but rather a passionate love of acting. The irony is that she needs to get her name known in order to land the bigger film roles. Hence she has a PR for the first time in her life. Her attitude to celebrity remains ambivalent, however. 'It must be nice to go to these parties and be a bit recognised, but I think I would just find myself in the corner, wishing all my friends were there, and going, "Why am I here?" I am not the most ambitious person in the world.'