The Gunners man was talking to Sky Sports Soccer AM and dished the dirt on his international teammates.
The winger isn’t in the squad during this international week, with England having beaten Lithuania on Friday evening and then taking on Italy in a friendly on Tuesday.
However, he has been a feature of several of Roy Hodgon’s squads in recent times, with one of his more memorable appearances in an England shirt coming in the win over Scotland.
Those experiences make him knowledgeable on the England camp, and he has now given Soccer AM an insight into the squad, naming Rooney as the best trainer of the bunch.
“Wazza [Wayne Rooney] is definitely the best trainer,” he said about Rooney.
“He scores lots of goals, he trains 100 per cent and he doesn’t mind putting in the odd naughty tackle if it means winning. He trains exactly how he plays and that’s how it should be.”
Training isn’t the only strongpoint that Chamberlain credits Rooney for though, saying he is also the hardman of the group.
That will come as surprise to many given the recent incident involving the United forward.
A video of Rooney was recently released by The Sun, seemingly showing him being knocked out in a friendly bout with defender Phil Bardsley.
The forward is well known to be a big boxing fan outside of football, and as far as Arsenal winger Chamberlain is concerned, he is without question the hardest man in the England squad, something which is likely to come in useful as captain.
“I’d have to say Wayne Rooney. He is definitely pretty hard,” he added.