The singer, who accepted the Brits 'Critics' Choice' award at the event, was introduced to the 'Poker Face' star later in the evening.
Writing on Twitter, she said: "Lady GaGa held my hand and we talked and I think I died. :-("
Both artists are signed to labels owned by Universal Records, who held an oriental themed afterparty.
Other guests included Florence Welch, Lee Ryan, Calum Best, Keith Lemon and Geri Halliwell.
In Full: Brit Awards 2010 - The Winners