Benteke has scored 15 league goals during his debut season in England following a £7m summer move from Belgian side Genk.
"Christian is brilliant to play with," Weimann told the club's official website. "He's been outstanding for us.
"He's got nearly twenty goals this season - that says it all really. It tells you how important he is for our team."
Chelsea and Tottenham Hotspur have both been linked with moves for Benteke at the end of the season.