"I am very excited to be playing the Fever-Tree Championships again. I have happy memories of reaching the final at the Queen's Club 10 years ago and also winning the doubles title," Djokovic said in a statement released by tournament organisers on Monday.
"The atmosphere is always great and I am looking forward to playing in front of the British crowd again. After the exciting events in Rome and Paris, I'm ready for new challenges."
Djokovic, beaten by Rafael Nadal in the 2008 Queen's final, traditionally opts against playing a pre-Wimbledon event, preferring to use a handful of exhibition matches to get his game ready for the grass courts.
It was in doubt whether the 12-time Grand Slam champion would be seen in England at all this year.
Speaking following the Cecchinato loss, he said: "I don't know if I'm going to play on grass. I cannot give you any answer. I'm just not thinking about tennis at the moment."
Djokovic hasn't earned a major title since competing his career Grand Slam by winning the 2016 French Open.
He has failed to reach the semi-finals in any of his last five Grand Slam appearances, while his last two Wimbledons have ended in a third round exit in 2016 and last year's quarter-final withdrawal due to the elbow injury that troubled him for several months.
But Djokovic, dogged by rumours that he no longer has the motivation and desire to return to the top, ho...