Villa and Alba played together at Valencia before the former's move last summer.
He told El Mundo Deportivo: "I speak regularly with Jordi, he strikes me as a good guy and he is a spectacular player that had always played as a winger until (Unai) Emery moved him to full-back and he has been incredible.
"He was also surprised at his performance because at the start he didn't like it a lot, but now he is happier as a full-back than a winger. He has spectacular offensive movement.
"Moreover, he maintains his position defensively and can do a great deal of damage to the opponent's defence despite starting from so far away. He is a player with incredible physical conditions. He is very young and still has a great trajectory ahead of him."