The Gossip Girl actress confirmed that she teamed up with the 'Lollipop' rapper on a track called 'Make It Rain'.
Explaining how the partnership came about, Meester told MTV: "I sent him a couple of my songs.
"He's been diggin' on them for a while. Then he heard ['Make It Rain'], and he was like, 'All right, I'm gonna kill it'. [He's] really optimistic, and super supportive of me, which I've really, really appreciated so much."
As for their studio time together, she added: "It was like, literally, 4 o'clock in the morning.
"He was so sick - he didn't even write anything down. He just, like, vibed to the music and dances. I don't even know how he does it; he's amazing."