Showing the Queen his trick, she breaks into a huge smile when she sees what's inside. Her Majesty, Sophie Wessex and Princess Beatrice can also be seen watching on with grins on their faces.
Captured by an ITV camera crew while the family enjoy a day out at Royal Ascot, the commentator can be heard exclaiming: 'Not sure what Mike Tindall just found in his top hat there!'
Mike and his wife, Zara, 38, are regulars at the races and the fun exchange between him and the Queen shows that they have a fun relationship with their royal relatives.
Tindall must have been feeling in a jovial mood as he was also captured making Beatrice shriek with shock and he and Zara were caught laughing with Prince William.
Royal Ascot is the most anticipated event on the racing calendar and runs from today until Saturday.