While rumors abound that Rihanna has been making advances toward actor Colin Farrell, another source says it's Ryan Phillippe who she is really smashing. Apparently, back on February 12th, during Grammy weekend, Rihanna visibly blew off (no, not in that way) Phillippe at the Gucci/Roc Nation brunch. But looks can be deceiving, and an insider tells Us mag that the two slept with each other that same night. "She thinks he's hot," the source says. "They totally had sex. And it wasn't even the first time. They initially hooked up when things were strained with [Rihanna's ex] Matt Kemp back in early December." According to the source, Phillippe and Rihanna got together again at Bing's Two Kings charity event on the 19th, but kept it under wraps there as well. Phillippe then reportedly went to her 23rd birthday the next day at her house in Beverly Hills, and while they kept their flirtations to a minimum, that was merely to keep their secret relationship from ending up on front street. "Clearly they're keeping it on the downlow," another source told Us.