Brook also hinted that she was ready to settle down with her boyfriend, England rugby star Danny Cipirani, 21.
She said: "I turn 30 next month and I see it as an achievement that I've got to this age without getting married and having children. Not that I've got anything against either, but I have been with so many guys who have said "You're mine.
Let's get married and have kids" and I have always said no because I have always wanted my independence and my own life.
"But now that I am with Danny, properly as a couple, I am looking forward to giving all that up."
She starts her new role in the West End production of Calendar Girls at the Noel Coward theatre next week but admitted she was slightly concerned about taking her clothes off.