Diane is a major character on the sitcom Cheers and a 'visitor' on Frasier. She was created for and primarily appeared on Cheers, for its first five seasons. She was a well-educated writer who became, of necessity, a barmaid at Cheers. She soon was wooed by Sam Malone, but later began dating the psychiatrist Dr. Frasier Crane. However, she eventually left Frasier at the altar and dated Sam again. She left after that, and returned only in the finale of the series.
Diane reappeared on the episode of Frasier, "The Show Where Diane Comes Back". In this episode, she is in a depression and hopes that Frasier can help her, as he helped her the last time. Frasier does, and eventually produces her play Rhapsody and Requiem. Frasier sees her play, only to be angered by the way he is perceived. Yet, he and Diane make amends, and they finally say goodbye.
- Diane is apparently disliked by both Niles Crane and Martin, a tradition earlier started by deceased Crane matriarch Hester Crane, who had threatened to kill her with a gun in her first and only appearance on Cheers.
- She is one of the few women that Frasier dated who has met Maris Crane (albeit offscreen), and commented on her being the "queerest little creature".
- Diane made an earlier appearance in a dream sequences in the episodes "Adventures In Paradise: Part 2" and later in the Season 9 episode "Don Juan In Hell: Part 2".