Carlos Cuellar has revealed that Darren Bent gave Sunderland a glowing reference when he asked about the club.
Cuellar joined his former boss Martin O'Neill on Wearside and thanked Bent for his advice.
"Darren was always talking up the club, the city, the supporters, the atmosphere, everything," he said.
The Spaniard is also delighted to be playing under O'Neill once again.
"It was an easy decision, having worked with the manager before," he added.
"I know the way Martin O'Neill likes to work and the way he wants to play."
Sunderland are about to embark on a pre-season tour of Asia ahead of their opening Premier League game against Arsenal on August 18.