The 14-time Grand Slam title winner lifted the Aegon Championships as part of an unprecedented treble with the French Open and Wimbledon titles in 2008 and joins defending champion Andy Murray in the line-up.
“I love playing at The Queen’s Club and I am very happy that I will be back this year,” said Nadal.
“I will never forget winning the title in 2008, it was a special moment, and going on to win my first Wimbledon. It is a very important tournament, very well organised and on some of the best grass courts in the world.
“Holding that trophy again would be amazing although I am well aware of the difficulties because the tournament always has so many good players.
“With Wimbledon just one week after, it is also important to be playing at Queen’s because it offers the perfect conditions and allows me to be with the British fans who always have given me great support.”
Nadal has played at The Queen’s Club six times before. On the five occasions that he reached the Wimbledon final, he played at The Queen’s Club beforehand.
“For Rafael Nadal to join our field of players so early is a huge boost to the Aegon Championships,” said tournament director Stephen Farrow.
“He is one of greatest and most popular players that has ever picked up a tennis racquet, and we know that our ticket-holders will be excited at the prospect of seeing him.”
The Aegon Championships take place at Queen’s Club from 13-19 June 2016.