Chris Brown and Rihanna were spotted in West Hollywood leaving and entering the same recording studio this week. 

Though they left separately, a spokesperson for Brown confirmed to E! News that the two are working on their second single together.

There is no hint as to what the song will be about, but based on previous songs they have worked on collaboratively; it will likely be about their unique relationship.

Brown already collaborated with Rihanna for the song, "Nobodies Business," which is featured on her seventh studio album, "Unapologetic."

Previously, they worked on the hit single, "Umbrella," together, then remixed each other’s singles, Rihanna’s "Birthday Cake," and Brown’s "Turn Up The Music."

The pair caused controversy when she featured him on the remix of "Birthday Cake," since on the track, Brown sings, "Girl I wanna [expletive] you right now. Been a long time. I’ve been missing your body. Let me turn the lights down. When the window go down, it's a private party."

Rihanna also sang on his song, "Turn Up the Music," saying, “"Turn up the music cause I feel a little turned on/ Turn on the music, don't you try to turn me down." She later says, “I love you baby.”

Many are not excited about the two working together as back in 2009, Brown infamously assaulted Rihanna, hitting her so forcefully that she had major contusions on her face, a split lip, and a bloody nose.

Brown eventually pleaded guilty to assaulting Rihanna and was ordered to stay away from her until 2011.

Since then, they had rekindled their romance, and have been seen in public together quite frequently.

In addition to working on another song together, this week Rihanna released the cover art for her latest single, "Stay," and it features her alongside her on-and-off again boyfriend.

This is not the first time Rihanna has stirred up controversy over her cover art. For her single, "Diamonds," her cover showed her rolling a blunt full of the jewels.

Ironically, Brown is on the cover of "Stay," after it was reported this week that Rihanna may have moved on from him after a love triangle that has been going on for almost a year with baseball player Matt Kemp.