LONDON (AFP) - British diving star Tom Daley and filmmaker husband Dustin Lance Black revealed they are expecting their first child in a Valentine's Day Instagram post on Wednesday (Feb 14).

The 23-year-old, who won 10m platform gold at last year's world championships in Budapest, posted a picture of the couple holding up to the camera a black-and-white image from a baby scan, with the message, "Happy Valentines Day!" to his 1.9 million followers.

"Tom and Dustin are thrilled to share that they are expecting their first child in 2018," said a spokesman for the Olympic diver.

His American husband posted another photograph on Twitter.

"A very happy Valentine's Day from ours to yours," he wrote with an emoji of a family of three. The couple were engaged in 2015 and married last year.

Daley, who has three world championships gold medals and two Olympic bronze medals, came out as gay in a YouTube video in 2013 in which he said he was "dating a guy and couldn't be happier" and he spoke last year about wanting children.

"We're not planning to have children immediately, but we do want them in the future," he told the Daily Mirror newspaper.

"I've always been a family person so I've always wanted kids, and I know Lance does, too. I don't know how many - an army of kids, a whole diving team.

"We're both lucky to have supportive families and we want to share that with our own children."