The 41-year-old comedian told fans on Twitter that his model wife was pregnant and that the couple will be welcoming their first child next year.
David told fans the couple were overjoyed at the news and said they both 'couldn't be happier.'
He posted: '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. Dx'
The couple released a statement on Thursday announcing the happy news, which read: '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.'
The couple already have plenty of practice looking after a little one, after welcoming dog Bert into their lives earlier this year.
Lara, who dubs herself 'Bert's mum' on Twitter, has joked about the differences between looking after an animal and having a child.
She said: 'A baby will probably never be as fun as Bert.'
As well as being a comedian and TV personality, Walliams has his own series of children's books too.
He will be able to read his quirky books, with titles including The Boy in The Dress, Mr Strink and Ratburger, to the new addition when the time comes.
The baby news has been revealed after Walliams spoke out about crippling depression which led him to try and commit suicide a number of times in his autobiography Camp David.
David and Walliams began dating at the end of 2009 before marrying at Claridge's hotel in May 2012.