World number one Andy Murray will defend his title at next month's Aegon Championships as six of world's top 10 men descend on Queen's Club in London.
The Briton has won the traditional Wimbledon warm-up event five times.
The tournament will also feature last year's beaten finalist Milos Raonic, 2012 champion Marin Cilic and 2008 winner Rafael Nadal.
Stan Wawrinka and David Goffin are also scheduled to play in the event which takes place from 19-25 June.
Jo-Wilfried Tsonga, Tomas Berdych, Nick Kyrgios and Juan Martin del Potro will also take part.
Tournament director Stephen Farrow said: "The player entry list for the Aegon Championships is strong every year and we already knew we were in for a great line-up, but with Cilic and Goffin adding their names to make it six of the world's top 10, this is going to be the best yet.