Grealish, a friend and team-mate of Abraham's during England age-grade call-ups, and Terry, Chelsea legend and claret and blue captain last season, both played their part in selling the club to the 20-year-old.
Abraham told avfc.co.uk: “I've had Jack Grealish messaging me every day telling me to come.
“It's nice to have someone that you know here. It helped make up my mind a couple of days ago.
“John Terry was also one of the first people to call me about the move. He said what a great place it was and how much he loved his time here.
“He said how much I'd like the manager and the players. I believe him and I've already enjoyed my first afternoon in and around the place."