In a nod to her Spice Girls persona, the mother-of-three sported a long-sleeved, high-necked, form-fitting leopard print dress to pose with her beloved dog Cookie while in a second photo she showed off her curls.
Along with an emoji of a leopard, the 45-year-old singer wrote: "Scary’s back BOOM."
It comes as Mel B, real name Melanie Brown, posted to the platform for the first time in several months.
Her last post made in June expressed support for the Black Lives Matter movement in the wake of the killing of unarmed black man George Floyd in the US.
Watch: Mel B reveals the reason she lost touch with her sister for TEN years
It prompted the Leeds-born star to share some of her own experiences with racism as a young mixed-race girl growing up in a predominantly white area.
She said: "I was aware from a very young age that I didn't see many other people of my colour.
"But it was really when I went to school that I understood the colour of my skin had such an effect on the other kids.”
She explained to the Daily Star how she had to learn to run fast as a youngster as kids would chase her and yell racial slurs on her home from school.
Meanwhile, as the Spice Girls prepare to celebrate their 25th anniversary next year, Mel C has hinted there could be another reunion tour on the cards as she's determined to "do everything in [her] power]” to make it happen.
Scary and Sporty got together with Emma Bunton and Geri Horner last year for a hugely successful UK tour, however, Victoria Beckham chose not to join them.
Watch: Mel C talks possibility of Spice Girls reunion