Paul Rudd is an expert comedian, but some of his impressions need a little work!

The 45-year-old was asked by fellow actor Nick Kroll to try out some celebrity voices at the Annual Big Slick Weekend in Kansas City, Mo, and among the attempted impressions were, Liberace, Jon Hamm, Rob Riggle and even Joan Rivers.

Although Paul nailed a few down and missed the mark on others, all of them were pretty hilarious!

The boys where in Missouri to raise money for the Cancer Center at Children's Mercy Hospital and were joined during the weekend by other charitable celebs including Jason Sudeikis, Modern Family's Eric Stonestreet and Olivia Wilde.