The teenager last played for Langley F.C, and now joins Rob Quinn’s Palace side.
He is a right-back with attacking attributes, and also has experience playing wing-back.
Speaking after putting pen to paper, Addae said: “I’m enjoying my time here and trying to give my all and give everything I can offer. It’s important for my family because they always knew I could do it.”
Academy Director Gary Issott added: “Josh is a talented young player who has impressed us in recent weeks. He needs to work hard on his tactical and physical development now he has this opportunity, and ensure he makes the most of the chance our Academy offers.”