Serena Williams has filed the necessary paperwork for a return to tennis - but then said she is "not coming back" to the sport.

The American great, who won 23 Grand Slam singles titles, retired after the 2022 US Open.

The International Tennis Integrity Agency has confirmed to BBC Sport that Williams, 44, is back on the list of players registered for the drug testing pool.

Her name also appears on the most recent document published by the organisation on 6 October.

Just hours after it emerged she had re-entered the sport’s registered drug testing pool, Williams posted on social media: "I'm NOT coming back. This wildfire is crazy".

Why Williams would ask for her name to be added, without any intention of playing again, remains a mystery - as joining the list invites a visit from out-of-competition testers.

Williams was never a fan of the word retirement, preferring instead to say she was "evolving away" from the sport in 2022.

Bill Clinton, Billie Jean King, Tiger Woods and Mike Tyson were among the crowd in New York three years ago as Williams won her first two singles matches at her final US Open.

Her career was eventually brought to an end by Australia's Ajla Tomljanovic in the third round, but only after Williams had saved five match points in an electric night session on Arthur Ashe Stadium.

Every retired player must make themselves available for out-of-competition testing for six months before they are eligible to compete professionally again.

It is not known exactly when Williams asked for her name to be re-added to the list, but, even if she had to wait six months from 6 October, it would make a return possible from April.

Only Margaret Court and Novak Djokovic have won more Grand Slam singles titles than Williams.

Her haul of seven Australian Open titles, three French Opens, seven Wimbledons and six US Opens is the most major singles titles by any woman in the Open era.

Serena’s older sister Venus made a comeback after 16 months off the tour earlier this year.

Seven-time major singles champion Venus competed in the singles and doubles at the US Open aged 45, reaching the last eight of the women's doubles alongside Leylah Fernandez.

Serena and Venus won 14 Grand Slam doubles titles and three Olympic gold medals together, and the prospect of a Williams sisters reunion in 2026 remains an enticing one.