She also credits her “funny” husband, 44, for keeping her young.
She added: “I’m lucky because Justin is the funniest person I’ve met, and we make each other laugh.
Read more: Inside Jennifer Aniston and Justin Theroux's romantic Valentine's Day
Jen also insists she is comfortable about her age.
“I feel better in my 40s," she said. "Not only do you feel better in your body physically but you’re mentally better.
Jennifer, who played Rachel Green in Friends , recently became overcome with emotion at a reunion of the iconic sitcom.
Read more: Friends cast confess they broke sex ban
She sobbed during a tribute to the director as she thanked him for "the opportunity of a lifetime" during the special televised event.
"We experienced friendship, family, heartbreak, babies, everything, together. And we also had a wonderful experience with the world loving us as well."
