Actress Blake Lively had a reason to get worried when she was in labour to give birth to daughter James, who is now two years old.

While playing a Fact or Fiction game with fashion designer Michael Kors, Lively said when she was in the labour, her husband and actor Ryan Reynolds started singing 1973 single "Let's get it on", after which the doctor started laughing, reports dailymail.co.uk.

"My husband played ‘Let's get it on' when I was in labour," Lively said.

"My doctor was laughing so hard that I thought she was going to drop our baby," she added, revealing her cause of worry.

The couple also have another daughter, six months old Ines.