Rooney scored from the penalty spot on Tuesday as the Rams dispatched League Two side Northampton Town 4-2 at Pride Park in the FA Cup fourth round replay.
Derby’s reward for advancing into the fifth round of the oldest club competition in world football will be a home date with Rooney’s former employers at the start of March.
Rooney spent 13 years at Manchester United after joining from boyhood club Everton in the summer of 2004.
The 34-year-old left Old Trafford as a club legend in 2017 as his 253 goals in 559 appearances sees him remain as Manchester United’s all-time leading goalscorer.
Rooney won five Premier League titles, one FA Cup and the UEFA Champions League among many honours as a United player.
The former England captain has already faced the Red Devils twice with Everton since leaving Old Trafford but his current manager believes their latest reunion will be one to savour.
“He’s going to face the club where he had a wonderful career so of course it is special,” Cocu said after the game.
“He comes back from the States, joins us and now plays his old club where he had a great career. We have to wait for a month but I’m sure he’ll be ready.
“It will be a beautiful game not just for Wayne, but everyone at the club. It’s a great game to look forward to and we will also try to win it, against a strong opponent.
Rooney has scored three goals in eight appearances since joining Derby as player-manager from Major League Soccer side DC United in December.
