Rihanna and Chris Brown ''haven't stopped'' texting since her birthday.

The 'Diamonds' singer - who was recently seen partying with another former boyfriend, Drake, in Paris - has reportedly caused friends to ''freak out'' as they are concerned she is planning to renew her romance with the 'Yeah 3x' hitmaker, even though she initially snubbed his messages.

A source told the New York Post newspaper: ''Chris started texting Rihanna on her birthday, February 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.

''Since then, the two haven't stopped texting each other and friends are freaked out that she's going to start dating him again.''

Chris - who recently underwent a 90-day rehab programme for anger management - first split from Rihanna in 2009 after he violently assaulted her, but they then had an on/off relationship after her restraining order against him expired two years later.

Following their separation, the 'Only Girl in the World' hitmaker romanced Drake, and in 2012, he got into a club row with Chris after sending him a note reading ''I'm f***ing the love of your life.''