London - Spain's world number one Rafael Nadal heads what organisers say is the most formidable line-up for Queen's, the historic grass tournament in London that is a key warm-up event for Wimbledon.
Aside from Nadal and five others from the present top 10 the tournament is likely to see Britain's two-time Wimbledon champion Andy Murray - a five-time winner of the Queen's title - play as he makes a comeback after hip surgery.
Other stars who are presently outside the top 10 such as Australian firebrand Nick Kyrgios and Switerland's Stan Wawrinka - who needs the Wimbledon title to complete a sweep of Grand Slam titles - have also confirmed they will play as will last year's champion Feliciano Lopez.
"To see six of the world's top 10 players on our entry list before you even get to the names Andy Murray, Stan Wawrinka, Milos Raonic, Feliciano Lopez, Nick Kyrgios and the British No 1 Kyle Edmund really whets the appetite for a fantastic week of tennis," said tournament director Stephen Farrow.
"We can't wait to get started."
The tournament runs from June 18-24.