X17 EXCLUSIVE - Rihanna And Chris Brown Have Secret Rendezvous At Recording Studio

Seems Chris and Rihanna are trying to keep their relationship on the DL ...

Chris visited Rihanna at the recording studio Thursday night after Brown hit up David Furnish's 50th birthday party.

Our photographer tells us Chris parked on the street and entered through the front door of the studio, while Rihanna was parked in the private lot behind the studio and exited through the back door to avoid being photographed together.

He tells us:

"Chris was all happy, acting like he was just headed to work or something, but we knew he was visiting Rihanna. We even asked him, 'He; you going to see Rihanna?' and he just kind of laughed. You kinda get the feeling he likes sneaking around."

This is one of a handful of times the former lovers have reunited since Brown broke up with girlfriend Karrreuche Tran. Chris and Ri were spotted out together Oct. 4 at Jay-Z's Brooklyn concert at the opening of the Barclay Center and then we snapped the two together at the Qubeey launch party in LA last week.

Last night, RiRi held on tight to her favorite Gucci bag, while Chris stood out front next to his pricey Lamborghini.

Uh, Karreuche Tran ... who?