Fiction set in the universe of 1984

Has anyone written anything set in the universe of the novel 1984? (Other than that novel itself of course!)

I’d be especially interested to find out that someone has written a backstory or even full biographical account for O’Brien.

I can think of two: one titled “Orwell’s Revenge” (a.k.a. 1994) postulates that the telescreens worked by something analogous to the Internet and that hackers learned to infiltrate and bypass it.unless the whole story was a Ministry of Truth propaganda piece, and another whose name I can’t find that takes a direct analogy to Stalinism, in which it turns out there was a literal Big Brother whose death forestalls Winston’s and Julia’s executions (very untrue to the original, imho).

From the “why does this exist” file, Swedish prog metal artist Ayreon’s debut album, “The Final Experiment,” is a rock opera set in the court of King Arthur about messages sent back in time FROM the future following George Orwell’s 1984. It’s one of the most needlessly complicated plots I’ve ever heard of.

The League of Extraordinary Gentlemen mentions it in the Black Dossier volume.

Found it. 1985 by György Dalos