Mel B, Scary Spice or - to give her her full title, Melanie Brown - is currently starring as Roxie Hart in the Broadway production of Chicago.
However, it seems that she just can't leave the past behind, as the below clip demonstrates.
The singer was midway through one of her final shows in the role on Sunday when she just couldn't stop herself from singing a few lines of 'Wannabe', saying 'I'm gonna tell you something... so here's the story from A-Z...' to the crowd's delight.
No doubt the director was also delightedly smiling through gritted teeth, because if there's one thing directors love, it's their actors breaking character and going off-script.
Watch the clip, posted by Brown herself to Instagram, below: