Posh shared a picture of them together on the red carpet of the Global Gift Gala on Friday night.
She posted: “So proud of @melaniecmusic X fantastic performance tonight!!! X #friendshipneverends #girlpower.”
The reunion came on the same night reports claimed the Spice Girls are set to announce a stadium tour for next summer on Monday - without Victoria.
According to The Sun, Mel B, Mel C, Geri Horner and Emma Bunton have recorded a video message that will be broadcast on Bonfire Night, ahead of an appearance on Jonathan Ross’s chat show the following Saturday.
However, Victoria is said not to be involved, choosing to focus on her fashion business.
Mel B heavily hinted Posh would not be reuniting with her bandmates earlier this week, when she used her Halloween costume to take a swipe at her.
She and a friend dressed as Victoria and husband David for a party hosted by Heidi Klum, with Mel carrying a battle-axe emblazoned with the message, “No I am not going on tour”.
‘David’ was also holding up a flag that read: “Please, please, please do it for the Spice Girls fans.”
While there have been whisperings about some sort of Spice Girls reunion since the 20th anniversary of ‘Wannabe’ in 2016, the band have so far remained quiet on what exactly what they’ve got in store for fans.
Back in February, Victoria fuelled rumours that she’d be joining her bandmates in some capacity for their reunion plans, when she posed for a photo with the rest of the group and shared it on Instagram - the first time all five had been seen together since the ‘Viva Forever’ premiere in 2012.
However, Victoria was quick to dismiss that the reunion would involve going on the road, telling Vogue simply: “I’m not going on tour. The girls aren’t going on tour.”
The Spice Girls, who formed in 1994, have not performed together since the London Olympics closing ceremony in 2012.
The group went on hiatus in 2000, after recording their third album, which came after Geri quit two years earlier.