Essien has been welcomed to the Rossoneri by Muntari, who believes that his Ghana teammate will settle quickly after joining on an 18-month deal from Chelsea.
"I'm convinced that he can give so much at Milan," Muntari told Milan Channel. "Me and my teammates are helping him to settle as soon as possible.
"We've been friends for 12 years; we have often shared a room when we are with our country."
Milan are currently ninth in Serie A.