The Oscar-winning actress stars with the comic actor in two new movies, 'The Tempest' and 'Arthur', but admits she was worried about how she would get on with the reformed hellraiser because she is a "good girl".
During an appearance on British breakfast TV show 'Daybreak', she said: "I'm a bit infatuated with him. But I was terrified because, you know, it's Russell Brand! Like the bad boy of Bad Boys. And I'm not a bad girl, I'm a good girl. And when good girls meet bad boys, Terrible Things can happen - mostly to the good girls."
Despite her concerns, Helen and Russell - who is married to Katy Perry - struck up a great relationship on both sets and she has nothing but praise for him.
The 65-year-old star - who plays Prospera in 'The Tempest', which is based on Shakespeare's play of the same name - said: "We did 'Arthur' together which was really wonderful and it kind of sealed our relationship. And there I got to see what an amazing guy he is - an incredible hard worker, kindest heart in the world, funny of course, he's a great guy."