The former world number one has been trying to recapture his top form after undergoing elbow surgery earlier this year and reached the quarter-finals of the French Open, where he was knocked out by Italian journeyman Marco Cecchinato.
After being treated for neck pain during that match, the 12-times Grand Slam winner cast doubts on his Wimbledon participation following his Roland Garros exit.
“After the exciting events in Rome and Paris, I’m ready for new challenges,” Djokovic, a runner-up at Queen’s Club in 2008, said on the tournament’s website.
“Grass is very special, it is the rarest of surfaces so I’m happy I’ll have the opportunity to compete at this strong tournament, which will also be a great preparation for Wimbledon.
“I have happy memories of reaching the final at The Queen’s Club 10 years ago and also winning the doubles title.”
World number one Rafael Nadal and Britain’s Andy Murray are also due to play at Queen’s Club, although question marks remain about the participation of both.
Following his triumph at Roland Garros on Sunday, Nadal said he was unsure about his grasscourt plans as he needs to see how his body will recover following a long claycourt campaign which culminated with him winning the French Open title for the 11th time on Sunday.
Murray, a five-times winner at Queen’s, has been out of action since last July with a hip problem and is expected to make his comeback at the London tournament next week, although he has already delayed his return by pulling out of a grasscourt event in the Netherlands this week.
Marin Cilic and Stan Wawrinka, whose ranking plummeted to 263 in the world this week after he too endured injury problems over the past year, are also in the draw.
The tournament begins next Monday, two weeks before Wimbledon starts on July 2.