The 21-year-old is currently on loan at Colchester United, but Forest have now canceled his loan early to sell him to the Scottish Premiership side where he spent last season on loan.
"I am absolutely delighted to be back at the club," he said. "As soon as I knew there was interest, it was a no-brainer to come back. My time here was excellent last season, really successful and I hope to pick up where I left off.
"There was a real connection with the fans and the players, and I'm looking to repay them for the great support. I can't wait to get back out in front of them.”
Forest’s head of academy Chris McGuane waved an emotional goodbye to the defender and wished him all the best for his future endeavors.
“We would firstly like to thank Danny Cowley and Colchester for their co-operation and treatment of Aaron since he joined them earlier this season. His game has reached another level this year and he now has an opportunity to continue his development playing top division football.
“He has been an asset to the Academy both on and off the pitch and we wish him all the best for this next chapter in his career.”