Charlie, a 21-year-old defender, has played the majority of his football in a Watford shirt, having started with their Under-18 side.
In November 2018, Rowan joined QPR and has since signed a contract extension which will keep the defender at Loftus Road until 2020.
Capable of playing both central defence and full-back, Charlie has been hailed for his versatility as a defender, and Darren Currie admitted he’s had his eye on Charlie for a while now.
He said: “Very pleased to get Charlie on board. He’s one that I’ve had my eye on over recent months.
“We’ve got friends at QPR that speak really highly of him as well.
“Charlie’s a young man who’s at the very start of his career. We’re delighted he’s joined us and we’re looking forward to working with him.”
Rowan’s deal is subject to confirmation from the regulatory authorities.