Lena Dunham was inspired to work out by her ''really hot'' parents.

The 'Girls' star is currently working hard to lose weight and credits her father Caroll Dunham and mother Laurie Simmons for inspiring her to ditch the pounds.

Pointing at a small step, she said: ''I wanted to do it because I was losing by breath when I walked up like that stair... And also both my parents, who are 65, they're both real exercise fiends, and it started in the last five years...

''My dad can lift these really heavy weights and do kettle bells. They can both jump rope and they look really hot, and I was just starting to feel like I was really dragging behind. I was like, 'You're more than twice my age, and I look like a bag of trash next to you!'''

Lena, 28, has now turned to acro-yoga in a bid to lose weight and says she is already feeling ''really good'' about the effects it's having.

Referring to a picture she posted on Instagram of her and a male companion in a yoga position, she told The Late Show with David Letterman: ''Believe it or not, that takes a lot of core strength!''

''I say this with a lot of love, but behind the wall of fat, they're doing a lot! I'm not trying to get you to go, 'Oh, Lena, you're not fat' - it's like, I feel great, I feel really good, I'm just recognising what's happening!...

''I'm gonna say that if I was this adventuresome in my early twenties, I would've had a better time in the boyfriend department.''