The 31-year-old world No. 2 has had a fantastic 2017 so far, claiming four titles and winning 46 matches.
Having struggled with injuries over the last two years, the 15-time grand slam winner looked to be back to his best form after winning Roland Garros and also having reached the final of the Australian Open in January, losing to Swiss superstar Roger Federer in five sets.
In an interview carried by the ATP website, Nadal said he was happy to have already qualified for London after a great start to the year.
“I’ve had a great season so far and I am happy to have already qualified for London,” Nadal said.
“I could not play last year because of injury so I look forward to returning in November.”
The ATP World Tour Finals is made up of the world’s top eight singles players and top eight doubles pairs and is scheduled to run from 12-19 November at the O2 Arena in London.
Besides Nadal, the other players in line to qualify for November’s tournament are: Australian Open champion Federer, Austrian Dominic Thiem, Stan Wawrinka, Alexander Zverev, Novak Djokovic, David Goffin and world No.1 Andy Murray.