It's official! IMDB now has Ian McDiarmid listed as Palpatine for Episode IX! : r/StarWars

Palpatine - Wikipedia

Ian McDiarmid - IMDb

Ian McDiarmid Hints At Emperor Palpatine's Return To Star Wars - Geekosity

Ian McDiarmid - IMDb

Palpatine - Wikipedia

Ian Abercrombie's Cause of Death: How Star Wars' Palpatine Actor Died

Ian McDiarmid - News - IMDb

SPECULATION: The Case for Darth Plagueis In Star Wars: Episode 7 . . . - Star Wars News Net

Palpatine - Wikipedia

First Official Image Of Ian McDiarmid's Palpatine From 'Star Wars 9' - Heroic Hollywood

Will Ian McDiarmid Return as Sidious? Or his new Vessel? (I hope Ian McDiarmid) - Star Wars Theory

It's paradoxical that seeing Ian McDiarmid play Palpatine again is, to me, both the worst and the best thing about The Rise of Skywalker : r/StarWars

Why did Star Wars start with Episode IV? - Quora

Darth Vader - Wikipedia

Star Wars 9: Emperor Palpatine actor Ian McDiarmid teases strength of Dark Side - Mirror Online