Lehmann was the coach of Deccan Chargers. But the Hyderabad franchise was terminated by BCCI for breach of contract. The new owners of Hyderabad team, Sun Network, hired Tom Moody as coach and did not extend Lehmann's contract.
"We are extremely happy to have Darren Lehmann on-board as the coach of our team. Darren brings with him rich experience and immense knowledge about the game and the T20 format through his stints with IPL and other leagues," the team said in a statement.
"We firmly believe that he will be a great mentor to our team and will take us to new heights. We wish him all the best for his endeavours," it added.
On his appointment, Lehmann said: "I am extremely honoured. The franchise has always excited me and I look forward to working with the owners, players, support staff and fans. I will always encourage our team to be an entertaining and aggressive brand that people love to watch and associate with."
He added that he was looking forward to working with Adam Gilchrist.
"I'm also looking forward to working with Adam Gilchrist again and help all the players grow on and off the field."