Karrueche Tran: Still Dating Chris Brown, Supposedly Aware of Rihanna Hookups

Earlier today, we reported that Rihanna and Chris Brown are hooking up ... according to one tabloid. Well, there's a new twist, and its name is Karrueche Tran.

Us Weekly claims Brown, 22, and Rihanna, 23, have been hooking up in secret for nearly a year, despite his present relationship with model Tran, also 23.

Chris Brown and Karrueche Tran were spotted together as recently as January 12, when he escorted his love to a hair appointment in Pasadena, Calif.

If Rihanna's driving a wedge between them, they're not showing it. Publicly.

Still, Tran is fully aware of his cheating, Us swears, and suspects she knows the locale: "Karrueche thinks Chris' studio is where most of the hookups take place."

She's determined to hang onto Brown despite the presence of the "We Found Love" singer. According to a source, Tran "won't give him up for a few discretions."

Warns the first insider: "Chris is a really passionate guy. He's still a hothead and he does what he wants. He'll go off the grid and she'll wonder what's going on."

"But, at the moment Chris and Karrueche are still a couple."