Answer
Suzanne Somers and Joyce DeWitt were the co-stars in Three's Company with John Ritter. The show was a sitcom that aired on ABC from 1977 to 1984. It starred Ritter as Jack Tripper, a man who pretends to be gay in order to live with two women in an apartment. Somers played Chrissy Snow, the ditzy blonde roommate, and DeWitt played Janet Wood, the more sensible roommate.