Spears was given the 'Michael Jackson Video Vanguard Award' at the ceremony in Los Angeles on Sunday night to honour her contribution to the music industry.
Spears accepted the accolade from GaGa while the 'Born This Way' star was in the guise of her male alter ego Jo Calderone.
The two popstars lingered and stared into each other's eyes as the award was handed over, moving in closer in a nod to Spears's notorious kiss with Madonna at the same awards ceremony in 2003.
However, Spears pulled out, joking: "I've done that already!"
The VMAs also staged a tribute to Spears during the ceremony. An array of dancers, all dressed in different styles from Spears's music video back catalogue, performed a choreographed routine to a mash-up of the popstar's hit singles.
Spears in turn went on to introduce Beyoncé, who took to the stage for the first time since announcing her pregnancy earlier today.
GaGa, as Calderone, opened this year's MTV VMAs with a powerful performance of 'You and I'.
