Chris Brown on Rihanna Song: 'I Miss Your Body'

Are Chris Brown and Rihanna getting cringingly close? Evidence is mounting that the relationship between the ex-lovers is percolating. Brown tweeted a happy birthday to Rihanna yesterday (in the wake of possible love tweets late last year), and Rihanna responded, triggering a tidal wave of OMGs and WTFs from startled fans, notes the New York Daily News. The two have also collaborated on not one but two new songs. The on-probation singer gushes: "I miss your body" on Rihanna's "Birthday Cake," and adds that he wants to do something with his missing Lady Love that does not involve punching (Rihanna's also featured on a new remix of Brown's "Turn Up the Music.").

Rihanna and Brown have been into some sizzling extracurricular activities, sources tell Us, even though he has (another) girlfriend. "Rihanna loves to live dangerously and talking to and hooking up with Chris is all part of that," said one. One singer not about to forgive Brown for his 2009 assault on Rihanna is Miranda Lambert, reports Good Morning America. She's keeping up her criticism with a new tweet, noting: "I don't get it. He beat on a girl." Check out Brown's (NSFW) contribution to Rihanna's song in the gallery, or listen to Rihanna on Brown's remix at the Huffington Post. (More Chris Brown stories.)