Roy Jones Jr. may be nearing a return to combat sports a little over a year after his last boxing match.

Former UFC star Vitor Belfort posted a video message he received from Jones on Instagram in which the retired boxer answered a challenge Belfort had issued for a ONE Championship event.

In the caption, Belfort wrote: "I am very excited for what's to come with @OneChampionship and this upcoming fight, I'm even more excited to be the first to bring you this new way of competition, it allows for the 1st time different worlds to collide in a way that's fair and exciting! Thank you accepting Roy and I am looking forward to this fight!"

In an interview with MMA Fighting, Belfort threw down the gauntlet for Jones. He said he'd be willing to fight the boxing legend in a special event where he'd be permitted to "dirty box":

Jones responded via TMZ Sports. "This is what I do for a living," he said. "Y'all must've forgot. That's who I am. I love a battle. I love a challenge. So, if that's what you want, that's what you get. Ain't like you gotta ask me twice."

Belfort signed with ONE Championship in February. The 41-year-old has been out of mixed martial arts since he lost to Lyoto Machida via second-round knockout at UFC 224 in May 2018.

Jones, who turned 50 in January, beat Scott Sigmon by unanimous decision in February 2018, which was the last time he stepped inside the ropes.

Belfort is 26-14 in his MMA career and captured the UFC light heavyweight championship in January 2004 when he beat Randy Couture. Jones is 66-9 with 47 knockouts professionally and held world titles in four different weight classes.