Los Angeles - Chris Brown and Rihanna can't stop texting.
The former couple - who split in 2013 - reportedly cannot ''cut off communication'' with each other but pals insist there are no romantic feelings between them.
A source said: ''Chris and Rihanna just can't cut off communication with one another. She actually wished Chris a happy birthday when he turned 25 last year, so he was returning the favour by wishing her many happy returns on Friday.
''They don't talk every day. Occasionally, one will reach out to the other once a month, but it's very harmless. They still have a fondness for one another, despite everything that went on, but don't have any romantic feelings.''
The 'Loyal' hitmaker was convicted of assaulting Rihanna in 2009 and previously had to spend time in jail after violating his probation.
His recent communication with the 'FourFiveSeconds' hitmaker - who turned 27 on Friday - is said to have upset his on/off girlfriend Karrueche Tran.
The source told HollywoodLife.com: ''Karrueche isn't happy about it. She doesn't think Chris should be contacting his exes and should concentrate on her.
''He doesn't listen, however, and likes to stay friends with former girlfriends, much to her annoyance."