The singer, who is currently touring in Europe, said that she cut loose after a wild night of partying.
She told Musicrooms, 'There's nothing better than an impromptu dance party with my friends. My track Last Friday Night (T.G.I.F.) is a song about debauchery because I had one of those nights in Santa Barbara. We went out to this place called Wildcat and got crazy.
We had a couple of beers and danced until we died, then brought the party back to the hotel room.'
But the 26-year-old wife of comedian Russell Brand said that the threesome in the song was purely fictional.
She added, 'Most of that song is actual truth, apart from the ménage à trois... unfortunately! But, yes, streaking in the park, that's what we did, so we had to write a song about it the next day!'