Britney Spears is "so grateful" to Elton John for collaborating with her on the new song Hold Me Closer.

The upcoming single, which the pair reportedly recorded in Los Angeles in July, marks the Toxic singer's first new music since her 2016 album Glory. It will be released on Friday.

Taking to Instagram on Wednesday, Britney thanked Elton for working with her on the special comeback track.

"Since most say they are honored TO KNOW ME SO WELL and only want happiness for me... you can bet your bottom dollar that THIS collaboration will heighten my year by joining your brilliant hands of play," the 40-year-old gushed. "Thank you for your generosity and just thinking of me to join you on such a brilliant song!!! How cool is it to be a background voice ON YOUR song!!! Sir Elton I did it thanks to your genius, creative, and legendary mind!!! I am so grateful!!!"

Alongside the note, Britney shared a teaser clip of Hold Me Closer.

The song appears to be a mash up of Elton's 1971 classic Tiny Dancer and his 1992 hit The One.

Responding to the post, the British music legend insisted that Britney did more than provide back-up vocals.

"More than a background singer, darling. Can't wait for everyone to hear what we've been working on!" he exclaimed.