Juan Martin del Potro has joined the line-up for the Fever-Tree Championships at Queen’s Club.

It means four of the world’s top six players will feature at the Wimbledon warm-up, which runs from 18-24 June.

Argentina’s Del Potro, 29, joins world number one Rafael Nadal on the bill, along with Marin Cilic and Grigor Dimitrov.

The tournament will also be five-time winner Andy Murray’s second appearance on his comeback from a hip injury.

British number one Kyle Edmund will compete for a fourth time along with defending champion Feliciano Lopez.

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Former US Open champion Del Potro moved up to sixth in the world rankings after winning 15 matches in a row on his way to successive titles in Acapulco and Indian Wells last month. Dimitrov is fifth and Cilic fourth in the rankings.

“This year has been a very good start for me and I would love to continue playing my best tennis on grass,” said Del Potro, a former quarter-finalist at Queen’s.

“It is always a very strong player-field, so I am excited to start my grass season at this amazing tournament.’

The Championships will be broadcast live on BBC television, radio and online.