Lambert admitted that his progression has been superb over the last year at Villa Park.
"I don't think he was first choice last year," said the Scottish boss. "He was in and out and fleetingly getting little cameo roles.
"This year he has found a niche for himself and broken into the Austrian international team, which is a great honour for him.
"He's playing extremely well for us and the great thing about Andreas Weimann is that you'll always get the same from him."