K Raghavendra Rao shares a special bond with Superstar Krishna's family and Mahesh Babu calls him 'Mamayya'. It's well-known that the 'Darshakendrudu' is also the director of Mahesh's first movie, 'Rajakumarudu'.
Mahesh Babu has wished Raghavendra Rao on his birthday. "Happy birthday, mamayya @Ragavendraraoba. Will always cherish the experience of working with an ingenious director like you. Wishing you the best of health and happiness always!"(sic), wrote the Superstar on his twitter handle, sharing a pic from the sets of 'Rajakumarudu'.
Ragalahari.com too wishes legendary director K.Raghavendra Rao a very happy birthday.