UFC legend Jon Jones has made a stunning U-turn on his retirement from mixed martial arts, claiming he has re-entered the company's drug-testing pool just two weeks after calling time on his career.

The 37-year-old's shock statement on social media comes a day after President Donald Trump announced he wants a UFC card to take place on the White House lawn during America's 250th birthday next July.

Last month, UFC President Dana White announced Jones would not defend his heavyweight championship and had retired, coming as a major disappointment to fans amid demand for a heavyweight title showdown with Britain's Tom Aspinall.

Now, Jones claims he has taken a huge step towards a comeback after re-entering the testing pool - though it remains to be seen whether that is definitely the case - while also hinting that he could return on a potential card at the White House.

The Daily Mail has reached out to the UFC about Jones' status both in the testing pool and with the company. 

'Fighting at the White House?' Jones posted on X. 'Just re-entered the testing pool, that lasted for about two weeks. Figured we’d keep everyone’s options open.'

After Trump made the announcement, one fan tried offered up his dream matchup at the White House: ''I wish it would be [Jon] Jones and [Tom] Aspinall. Hopefully, they can talk him out of retirement. That would be the biggest fight in UFC history.'

Jones is considered the greatest heavyweight in UFC history, if not one of the most talented mixed martial artists of all-time. 

The legend was never properly defeated in his career, as the two fights not counted as wins on his record are a disqualification loss, due to an illegal strike in 2009, and a no-contest, which was originally a Jones knockout of fellow UFC legend Daniel Cormier.  

The 250th birthday of America will fall on a Saturday, which coincides with the day of the week most major UFC events are held. 

White has been a staunch supporter of Trump, hosting him at several UFC events over the last year. White also spoke on stage in Florida as part of Trump's acceptance speech after winning the Presidential election over Kamala Harris in November. 

Last year at UFC 309, moments after Jones' last victory, a knockout of Stipe Miocic at Madison Square Garden, he danced like Trump in the middle of the cage, much to the then-President elect's amusement. 

Jones and Trump shared a moment together feet from the Octagon with both holding the championship belt.