In these days of GDPR and whatnot, this seems like a bit of a silly move by Tesco. Unless of course, they were doing it for the publicity, if so, well played.
The ad is for the supermarket's new Clubcard Plus and features a photo of Mel B performing in the Spice Girls at the Brit Awards in 1997.
There's a speech bubble beside her saying, "Stop right now. You get 10% off two big shops a month for £7.99."
Mel B posted a picture of the ad at a bus stop (no doubt it was sent to her and she wasn't actually standing at the bus stop) with a caption reading, "Can the CEO OF TESCO DAVE LEWIS PLEASE CONTACT ME URGENTLY. Thank you."
https://www.instagram.com/p/B4url90prVb/
The image has now been removed from the campaign and order has been restored to planet Earth.
*Update: Mel B says her issue with Tesco ad was a "miscommunication"