Dr. Dan Grimaldi is an American actor who is known for his roles as twins Philly and Patsy Parisi on the HBO TV series, The Sopranos. In addition to his role on The Sopranos, he has also had some minor film credits, most notably as mother-fixated pyromaniac Donald 'Donny' Kohler in the 1980 slasher film Don't Go in the House, and some guest TV appearances, including several episodes on Law & Order. He also voices 'Frank' for the bestselling computer game "Mafia"
Despite the fact that Grimaldi is often cast in "tough-guy" roles, he is in fact highly educated. He holds a bachelor's degree in mathematics from Fordham University, a master's degree in operations research from New York University, and a Ph.D. in data processing from the City University of New York, and teaches in the Department of Mathematics and Computer Science at a Community College in Brooklyn, New York