David Walliams and Lara Stone lost the ''fun'' from their marriage.

The couple - who have 22-month-old son Alfred together - are reportedly on a trial separation but the 43-year-old comedian is keen to do whatever it takes to build a reconciliation.

A source said: ''They adore their son but Lara also loves to have fun and a lot of the fun has gone.

''They're both aware they have not spent enough time together but David really wants to change that.''

It has been claimed that Lara disliked her husband's camp public persona, and he hated her increasingly sexy image, but insiders insist the biggest problem is their heavy workloads.

The source said: ''Lara and David are just victims of their own amazing success. They both have incredible careers; he is always working - he has books, TV shows, films and offers coming out of his ears - and she flies around the world non-stop because she's one of the most successful models of her generation.''

Friends are said to be particularly concerned about David since Lara, 31, left their London home with Alfred and their dog Bert.

The source told Grazia magazine: ''David is in pieces. His friends are really worried because he hasn't talked about it.

''He keeps everything hidden with a big smile and a busy schedule, but everyone knows how much she means, how much his family (and) his son means.

''Splitting up for good is not something he will entertain.''