Geri Horner has been working with Ronnie Wood.
The former Spice Girl originally met up with the Rolling Stones rocker to get some advice on her upcoming album but the pair have now decided to hit the studio together to work on some tracks.
A source told The Sun newspaper: "They have been friends for a while but it's a shock that they've actually worked on a song."
Meanwhile, it was previously revealed Geri is considering having a folk sound on her new LP.
An insider said at the time: "It's going to be a new, much more mature sound for Geri. A few songs sound very folky, but there are other styles as well. It tells a story of her life."
And whilst Geri continues work on her solo career, rumours circulate about the possibility that the 90s girl group will make a comeback next year, with Geri admitting she finds it "really flattering" that they have that support.
She said: "I think it's really flattering that people are still supportive of the Spice Girls individually and collectively, that's beautiful, it's really nice.
"It almost feels you know that it (the Spice Girls) belongs to everyone, like a generation. So I think it's one of those things that's been discussed, but until it's concrete I wouldn't announce it."