Perry tries to heal rift with Rihanna

Katy Perry appears to have ended her feud with Rihanna.

The 'Part of Me' singer - who allegedly fell out with her best friend last October because of the 'Stay' singer's reconciliation with Chris Brown, who is still on probation for beating her in 2009 - reached out to Rihanna on her 25th birthday on Wednesday and admitted she was sorry she wasn't with her to celebrate.