The 38-year-old actress said she hasn't always been so confident in her appearance and it was only after meeting her husband Len Wiseman that she learnt to love herself, reported Daily Mail.
"Feeling attractive didn't come until I was 29 and with Len at the time it was partly perceived as if I'd gone all Hollywood, but it wasn't like that at all. It was just ok for me to walk around and feel feminine and attractive. I like feeling liberated like this," she said.
Beckinsale said being labelled one of the sexiest women in the world isn't always a good thing.
"I think the risk of being the sexiest woman alive is that you don't want to ever wear a bikini again," she added.
Beckinsale said she is now happily ageing with grace.
"What is it about a woman being in her late 30s that brings out the 'Oh, my gosh, are you worried?' questions? Worried? What about? 38, 39, 40, 50! Great! Still alive!
"I haven't experienced a full facial collapse, I haven't suddenly gained 20 pounds that won't go away, or a beard. That probably will happen, but it hasn't yet," she added.