According to Sir Ian McKellen (Freddie Thornhill), he and Sir Derek Jacobi (Stuart Bixby) went to drama school together, and both had crushes on each other, but never admitted it at the time, and so never entered into a relationship.
Freddie Thornill (Sir Ian McKellen) mentions several times that he was in Doctor Who (2005) and was voted 10th Popular Villain; McKellen did actually voice the Great Intelligence, a popular villain, in the The Snowmen (2012). His co-star Sir Derek Jacobi (Stuart Bixby) has also appeared as Professor Yana/The Master in Utopia (2007).
The series was loosely inspired by Staircase (1969), which starred Sir Rex Harrison and Richard Burton as a pair of aging Queens, exactly like Freddie Thornhill and Stuart Bixby in this series.
The show was originally titled "Vicious Old Queens", but this was thought of as too obscene, and so was shortened to just "Vicious".
The first mainstream British sitcom about a homosexual couple.