"He has a good heart - as long as we speak about private things.
"But when he stands on the training ground, he becomes a different person. The way he acts there sometimes needs getting used to."
Hleb does not believe boss Arsene Wenger was plotting to replace Lehmann, 38.
He said: "I don't think it was part of a big plan from Wenger. Jens had a few problems, that's why Almunia got his chance. Almunia is very popular."