But Hart says it wasn't a hard decision to move to east London.
"I've always loved the Club. I think you'll struggle to find anyone, apart from the direct opposing fans around London, who doesn't love the Club," said Hart.
"It's got something about it, it's got a lot history and I've always loved playing against West Ham.
"We've moved into London Stadium and we've got Slaven in charge who I've spoken to and I've always enjoyed as a manager.
"He obviously did a good job with Croatia and he's doing a good job here, so to get the opportunity to come here, it wasn't really a hard decision."