Rangers coach Mark Warburton said Brendan Rodgers would a "great choice" for Celtic as the Scottish champions close in on Ronny Deila's successor.
Former Liverpool manager Rodgers is reportedly the frontrunner to take the reins after Deila vacated his post in the wake of Celtic's fifth consecutive Scottish Premiership title.
Celtic owner Dermot Desmond has already talked up Rodgers and his coaching abilities as the Glasgow club also consider Neil Lennon, Roy Keane and David Moyes.
But rival coach Warburton, who worked alongside Rodgers at Watford, has backed the 43-year-old for the job as Rangers prepare for life back in Scotland's top flight.
"I know Brendan, I worked with him at Watford. I was academy manager and he was manager," Warburton said.
"He's very experienced, well organised, a good motivator, a good man-manager. He's a manager of the highest quality.
"He's worked in the Premier League and came within a slip of winning it, so there's no doubting Brendan's qualities.
"I like him very much as an individual, so if he is the man, he would be a great choice."