Cannavale is best known for his work on "Will & Grace" and Paulson starred in the short-lived series "Studio 60 on the Sunset Strip."
"In 'Cupid,' Trevor (Cannavale) is a larger-than-life character who may or may not be the Roman god of love, Cupid. Trevor insists that he was sent to earth to bring couples together," ABC said in a news release. "As fate would have it, he is under the care of famous psychologist and self-help author Dr. Claire Allen (Paulson,) who is also dedicated to helping lonely hearts find their soul mates. While she agrees with his cause, she questions whether he's crazy or really is Cupid."
The series, which is slated to air later this season, co-stars Rick Gomez from "What About Brian" and Camille Guaty from "Las Vegas."
"Veronica Mars" creator Rob Thomas serves as executive producer and writer on "Cupid."