Heroes star Hayden Panettier was forced to grow up when she embarked on her first trip abroad without her mother.

The 18-year-old actress flew to Europe last year to promote the hit TV show with her castmates, and it was the first time the star had left the U.S.

without being accompanied by a parent.

And the teenager insists the trip was a life-changing experience.

She says, "About five days after I turned 18, I took off to Europe with them (Heroes castmates). It was the first time that my mother hasn’t travelled with me and we went to Munich, Paris and London.

"It was such a different experience, being on your own and it changed me dramatically. My mum says that one person walked onto that plane and another person walked off."