Gaga also shared a photo of herself with Spears. In the photo, Spears wore a large blonde wig and a sequin bodysuit. Gaga wore a black long-sleeve dress and dark sunglasses.
Spears took her place at Saturday at the Planet Hollywood in Las Vegas. She began her two-year residency at the hotel in December.
Britney Spears said that she would love to collaborate with Lady Gaga. Spears told Saturday Night Online, "I would do a duet with Lady Gaga. I think that would be a lot of fun. I think she's very different and interesting and intricate."
Fans are now hoping for a duet that sounds like Gaga's "Telephone" or Spears' "Quicksand."