The British comedian announced his model wife's pregnancy on Twitter this afternoon (November 15).
"Some wonderful news. My beautiful wife Lara is pregnant," he wrote. "We are having a baby!"
He added: "It is due next year and we both couldn't be happier."
The Britain's Got Talent star married the Dutch model in May 2010.
In September 2010, Walliams commented that he had hopes of having daughters with Lara Stone.
Walliams is said to have signed a deal worth around £800,000 to return to Britain's Got Talent in 2013.