Tennis fans witnessed a rare treat when two of the greatest names in the sport took part in a match on a grass court aboard a barge on the River Thames.
John McEnroe and Monica Seles squared up as the boat passed the London Eye, the Tate Modern and Tower Bridge.
Monday's event promoted Wimbledon for all those who cannot make it to SW19. Games are to be shown on big screens near Tower Bridge from 1-4 July.
The court is to be put on dry land near the bridge to host charity matches.
R 'n' B singer Alicia Keys will also perform at a free concert there on Thursday night.
Funds raised at the celebrity tennis matches will go to the BBC backed Sport Relief charity.