Grand Slam winners Stanislas Wawrinka and Marin Cilic will play in the Aegon Championships at Queen's Club this summer.
Wawrinka broke the stranglehold of the 'big four' of men's tennis - Novak Djokovic, Rafael Nadal, Roger Federer and Andy Murray by winning the Australian Open last year, while Cilic's victory at the US Open in September was also a big surprise.
Cilic, the 2012 Queen's winner, and Wawrinka join Murray, defending champion Grigor Dimitrov and Lleyton Hewitt in committing to the tournament, which is a Wimbledon warm-up on grass and begins two weeks before the third Slam of the year on June 15.
Dimitrov won last year's tournament by defeating Spanish grass-court specialist Feliciano Lopez in the final.
