Duchess Catherine has made her first public appearance since the birth of Prince George.

The Duchess of Cambridge - who gave birth to her first child with Prince William, 31, on July 22 - made the last minute decision to join husband William as he officially started a 135 mile round-the-island marathon in Anglesey, Wales, earlier today (30.08.13).

A source told the MailOnline: ''Initially the duchess wasn't going to attend but she was also keen for the chance to thank the people of Anglesey herself for the warmth and hospitality they have shown her and the Duke.''

William was in good spirits and got the crowd laughing as he cupped his hand to his ear when he heard a baby cry and said: ''We're hearing a bit of that at the moment!''

Catherine, 31, added: ''He [George] is sleeping at the moment for now - fingers crossed!''

The brunette beauty - known as Kate Middleton before she married into the British royal family - wasn't expected to return to public duty until September 12.