Katherine Heigl has accepted she won't be "the ingenue forever".

The 46-year-old actress achieved many of her career ambitions during her 20s, when she starred in movies such as 'Knocked Up', 'The Ugly Truth' and '27 Dresses' - but Katherine accepts that she's now entered a new chapter in her life.

The Hollywood star told Us Weekly: "I wasn't thinking about [ageing] in my 20s, right? In my 20s, I was sort of at the height of my career, and I was getting to do all the roles I had always wanted to be able to do.

"I started as a child actor but by the time I got into my mid to late teens, you know, I was dying to be the romantic lead. I was dying to do some comedy. So I was so excited and on cloud nine getting to do what I had been sort of hustling to do for so many years. And you don't think about the expiration date on it."

Katherine concedes that she's now entered a different phase in her career.

The actress explained: "When I turned 40 I realized, 'Oh, that's pretty much over.' Like, there's a young generation that's coming up and I had my time and it was glorious, and it's kind of done now.

"And not to say that I can't be the romantic lead in something at 46 - that women in their 40s don't have a romantic love life or that they aren't funny or that, you know, they can't be the lead of a story. Of course they can.

"I am still the star of my own life. I find it interesting and compelling. I feel like others would, as well. And I feel like so many women in their 40s and 50s and 60s have compelling, interesting lives that we'd all be interested in seeing.

"So it's not to say, like, 'Oh, you can't do that anymore.' It's going to be very different. You're not the ingenue, and the ingenue is really a valuable role in Hollywood. And it's sort of, as you get older, you have to fight and say, 'Yes, but I am still a value and it might look different and it might feel different, but trust me, the story's worth telling.' It's a different fight."