"Chris started texting Rihanna on her birthday [Feb. 20], and the two have been sending each other a flurry of texts ever since. Rihanna didn't write back right away . . . but later that night she started getting sentimental and texted back, 'thank you,' and asked how he was," our source added. "Since then, the two haven't stopped texting each other and friends are freaked out that she's going to start dating him again."

Another source familiar with situation said it was Rihanna who initially reached out to Brown, to tell him she "missed him," before she flew off to Paris to meet Drake on tour.