The Layer Cake and Factory Girl actress and her actor fiance Tom Sturridge became parents in July to a daughter, Marlowe.
She said: "My life is really different, it's much better. People told me not to have kids, but I think motherhood's got a bad rep -- I don't feel compromised. In fact, I don't want to be anywhere else except with her."
Miller (30) also told how boxes of birds were thrown at her as she played Tippi Hedren in BBC2's The Girl, about Alfred Hitchcock's obsession with the actress he cast in The Birds.