Chennai: Prime Minister Manmohan Singh and BJP`s prime minsterial candidate Narendra Modi were among the leaders who greeted Tamil Nadu Chief Minister Jayalalithaa on her 66th birthday on Monday. Singh greeted Jayalalithaa over the telephone this morning and the Chief Minister thanked him for it, an official press release said. Modi in his message on social networking site Twitter said, "Birthday greetings to Tamil Nadu Chief Minister Jayalalithaa ji. I pray for her long life & good health."