Jon Jones said he has vacated his UFC light heavyweight belt in a social media post on Monday.
Jones – widely regarded as one of the greatest mixed martial arts fighters – previously announced in May that he was giving up his UFC title amid a pay dispute.
But the 33-year-old American star, who has been champion since December 2018 and boasts a 26-1-0 MMA record – wrote via Twitter: "Just got off the phone with @UFC, today I confirm that I'm vacating the light heavyweight championship.
"It's officially up for grabs. It's been an amazing journey, sincere thank you to all my competition, UFC and most importantly you fans."
However, Jones then tweeted two hours later: "Just had a really positive conversation with @UFC.
"Sounds like there will be negotiations for my next fight at heavy weight. All good news, the weight gaining process begins."
Jones has not fought since his unanimous decision win against Dominick Reyes at UFC 247 in February.
"In good faith I will be staying in the testing pool for probably the next half year or so," he added. "I'll continue to lift weights and train all the different martial arts."