Both singers have been pretty busy of late.
Emma Bunton, aka Baby Spice, is working on a reunion-collaboration with fellow former Spice Girls Mel B and Geri Horner (née Halliwell).
Meanwhile, Gaga has just released a new single called Perfect Illusion and is working on a new album.
The two hung out at Heart FM radio show in the UK earlier today.
They make a pretty neat duet as they sing Spice Girls' 1996 hit 2 become 1.
Check it out: