The happy couple announced the news in a statement, reported Daily Mail online.
The Dutch beauty, who landed on Number 8 of Forbes' top-earning models list said, "We're very excited to announce we are expecting our first child. We're both absolutely thrilled but ask you to please respect our privacy during this precious time."
Willaims also announced the good news via Twitter.
"Some wonderful news. My beautiful wife Lara is pregnant. We are having a baby! It is due next year and we both couldn't be happier," he said.
The 28-year-old model and the 41-year-old actor started seeing each other in September 2009. Williams then popped the question to her in January 2010.
The same year, the couple tied the knot here.
Williams is currently one of the "Britain's Got Talent" judges. The co-creator and star of "Little Britain" also starred on British sitcom "The Royal Bodyguard", which ended its run in January this year.
Stone is currently the face of Calvin Klein's 2012 Underwear campaign. She is also listed on models.Com's Industry Icons after getting the first rank on Top 50 Models list starting from Spring 2010 until this summer.
