The singer, 42, was asked about the usual Spice Girls reunion rumours when she revealed something very unexpected.
After impressing fans with her own solo music throughout the 2000s, the former Baby Spice confirmed she is now working on new material.
“This is the first time I’ve said: I am back in the studio,” she said on This Morning.
“I’m saying this on here because Phillip [Schofield] loved [past material].”
When hosts Phillip Schofield and Holly Willoughby reacted with excitement, she continued: “I am in the studio having fun with some music on my own.
“Just to see whether it works.”
Bunton has so far released three solo albums; the first of which, 2001’s A Girl Like Me, peaked at No4 in the UK and yielded the No1 single What Took You So Long?.
She followed it in 2004 with Free Me, which is thought to be her biggest-seller in the UK.
It yielded the singles Free Me, Maybe, I’ll Be There and Crickets Sing for Anamaria, all of which reached the UK Top 20.
Then in 2006, after a stint on Strictly Come Dancing, she brought out Life In Mono, which struggled to No65.
Its final single, All I Need To Know, only made it to No60.
Since then she has recorded very rarely; collaborating with former bandmate Melanie C in 2012 on I Know Him So Well.
The Spice Girls have been frequently rumoured to be plotting more concerts, but these have not been confirmed – with Victoria Beckham seemingly against the idea.
The group shot to fame in 1996 with the single Wannabe, and went on to become one of the most iconic British music acts of all time.