Sebastian Prodl suggests Per Mertesacker has been an influential figure since he joined Watford.
The Austrian defender played alongside the Arsenal star at German club Werder Bremen and has revealed that the World Cup winner has helped him settle after making the move to the Premier League.
"When I first signed here I met Per in London and he gave me some good recommendations about the area, because their training ground is nearby," he told the club's official website.
"He also gave me a good feeling about coming to the Premier League. He knows me as a player and as a human, so he recommended that I come and I'm very excited about it."