Following rumours that the pair had secretly recorded a duet together, a version of his 1971 hit Tiny Dancer, retitled Hold Me Closer, Sir Elton has teased the announcement on social media.
The 75-year-old Rocket Man singer shared a picture on Instagram of temporary artwork for the single cover that reads: "Hold Me Closer" followed by a rose emoji and a rocket emoji.
The rose emoji has become Spears' signature on social media, where she regularly updates her 41.9m followers, while the rocket represents Sir Elton.
Spears, 40, shared a video of herself dancing, with no sound.
She captioned the clip: "No music ??? Why is silence so loud ??? So loud you could almost cut it !!!"
This has been interpreted by some as a hint she is about to make an announcement about a musical comeback.
The Oops... I Did It Again! singer has not recorded any new music since her ninth studio album Glory in 2016.
She pulled out of a second Las Vegas run due to stress and has not performed since October 2018.
Last year saw the termination by a judge of the conservatorship which had controlled her life since 2008.
Her ex-husband Kevin Federline has just given in a tell-all interview about the star, claiming that their teenage sons - 16-year-old Sean Preston and 15-year-old Jayden James - choose not to see her and are embarrassed by her nude photos on Instagram.
Spears hit back in a statement on Instagram: “It saddens me to hear that my ex husband has decided to discuss the relationship between me and my children.
“As we all know, raising teenage boys is never easy for anyone. It concerns me the fact that the reasons is based on my Instagram… it was LONG before Instagram.
“I gave them everything… Only one word: HURTFUL… I’ll say it… My mother told me ‘You should GIVE them to their dad’.
“I’m sharing this because I can… Have a good day folks!”
Comments by Federline, 44, in the soon-to-air interview included claiming that he had told their sons about Spears' nude selfies: “I try to explain to them, ‘Look, maybe that’s just another way she tries to express herself’.
"But that doesn’t take away from the fact of what it does to them. It’s tough. I can't imagine how it feels to be a teenager having to go to high school.”
He also added: "The boys have decided they are not seeing her right now… It's been a few months since they've seen her."
Talking about her recent wedding to Asghari, he said: "They were happy for her but as they’re not seeing her right now, they made the decision not to go to her wedding.”
Federline also claimed the controversial 13-year conservatorship put in place by her father Jamie Spears, which came to an end in November 2021, had "saved her life".
Spears and Federline were married from 2004 to 2007.
Watch: Kevin Federline claims Britney Spears' 13-year conservatorship 'saved her life'