Lovell, who scored 15 goals for the relegated Dees last season, will join the Dons in a deal worth around £250,000.
Jimmy Calderwood is delighted to have secured his fifth signing of the summer, and he told RedWeb: "It's well known that Steve is a player I've targeted for some time and he's a cracking addition to the squad, particularly as it looked like we had lost out to Leicester in the chase to bring him on board."
The new boy added: "I had the chance to move down south but I always wanted to stay in Scotland if I could. Aberdeen is a very big and ambitious club that is on the up right now and I'm really looking forward to being a part of that. While I enjoyed my time at Dens, I'm an Aberdeen player now and I'm just looking forward to repaying the faith the manager has shown in me by being a success at Pittodrie."