The pair are said to have become very close in recent months, and now their friendship has turned into a professional one as both ladies have been getting creative in the studio.
The recording sessions will raise questions over the possible formation of a supergroup made up of members of both girl bands.
The band supported Girls Aloud on their Tangled tour in 2008 before heading out on their own, The Work Tour, in 2009.
After four albums and a handful of top ten hits they announced their permanent hiatus in 2014. King created a collection for high street chain Oasis, called Loved by Mollie, in 2013 and was also signed to Next Model Management.
Speaking to Hunger magazine about her new single, Vanessa confirmed that she would not be returning to the group. "As time goes on, I know it just wouldn't feel right for me." Her Saturdays bandmate, Frankie Bridge, has said the girls would be heading back to the studio to make music in 2016 but that hasn't been the case.
"I don't think I could go back," Vanessa explained. Frankie later said that she music wasn't exciting for her anymore.
Following in Frankie’s sparkling foot steps, Mollie will officially be competing in the BBC’s Strictly Come Dancing.
Paired up with AJ Pritchard, David Gandy’s ex has been tipped to go far as she competes against the likes of Aston Merrygold and Alexandra Burke.
In the same year she auditioned to become a member of new girl group The Saturdays with Una Healy, Vanessa White, Rochelle Humes and Frankie Bridge.
Vanessa, 27, who reportedly split from her boyfriend recently, is looking to go into the Australian jungle for the 2017 edition of the reality show as a ‘first signing’, while Mollie was the first contestant revealed for the BBC dancing competition earlier this month.
A source told uk: ‘Vanessa really surprised people with the launch of her solo career.
Marvin Humes’ wife has only recently given birth to the couple’s second child, Valentina.
Rochelle has also taken to presenting as she fills in for Lorraine and also hosts Ninja Warrior.