Andy Murray will have a tough field to get through if he wants to successfully defend his title at Queen's as 16 of the world's top 30 players have been confirmed in the lineup.
Rafael Nadal, Stanislas Wawrinka, Jo-Wilfried Tsonga and Milos Raonic will try to take Murray's Aegon Championship title in June.
Marin Cilic, Richard Gasquet, Juan Martin del Potro, Nick Kyrgios and John Isner have also confirmed their places in the tournament, which is used as a warm-up to Wimbledon.
Queen's runs from June 13 to 19, while Wimbledon gets underway on the 27th.