Among the field is Russian Ian Nepomniachtchi, who won the event last year before losing the World Championship match to Norway's Carlsen 7½-3½.

Nepomniachtchi, the world number seven, will be competing neutrally under the International Chess Federation (FIDE) flag due to sanctions imposed after the invasion of Ukraine.

His compatriot Sergey Karjakin, who unsuccessfully challenged Carlsen in 2016, will not be playing however after he was banned by FIDE for six months for publicly supporting the invasion.

FIDE said he had breached the organisation's Code of Ethics and he was unsuccessful with an appeal.

Karjakin's withdrawal means China's world number two Ding Liren comes in as the highest ranked player not already in the field.

Also playing will be Poland's Chess World Cup winner Jan-Krzysztof Duda and France's Alireza Firouzja, the winner of the FIDE Grand Swiss Tournament 2021.

American Hikaru Nakamura and Hungary's Richárd Rapport, the winner and runner-up respectively in the FIDE Grand Prix, will also challenge alongside another United States player in Fabiano Caruana, who was second at the Swiss event and lost the 2018 final to Carlsen.

Teimour Radjabov of Azerbaijan has a spot in the competition as a FIDE nominee.

All of the players will face each other twice in a double round robin at the Palace of Santoña in Madrid.

The event is due to end on July 5.