Prabhakar is the husband of Union Minister of State for Commerce Nirmala Sitharaman.
Previously, he was in the Congress and the BJP, after which he joined the Praja Rajyam Party (PRP) floated by Telugu movie actor Chiranjeevi.
He quit the PRP ahead of the 2009 elections after differences with Chiranjeevi and his brother-in-law Allu Aravind.
Since then Prabhakar stayed away from politics even as his wife Nirmala Sitharaman rose up the ranks in the BJP and went on to become a Union Minister.
AP Chief Secretary I Y R Krishna Rao issued the formal order on Prabhakar's appointment tonight.
Terms related to the appointment will be issued separately, the order said.