The British actor was almost unrecognizable on Monday when he donned a pink satin dress, a blonde wig and heavy makeup while promoting his show Blunt Talk in Los Angeles.
"Something is happening in Hollywood tonight. #blunttalkseason2," Stewart captioned an Instagram picture of himself getting all dolled up for the event.
Social media users took notice of the 75-year-old's new look, with some comparing Stewart to Helen Mirren.
"Glorious. Well done sir. Helen Mirren, amirite?" one tweeter wrote.
Another Twitter user quipped, "channeling Helen Mirren there."
Something is happening in Hollywood tonight. pic.twitter.com/hhDTqOtBx5— Patrick Stewart (@SirPatStew) April 19, 2016
The 75-year-old was joined by stars Jacki Weaver, Elvis Mitchell and Adrian Scarborough at the event, which included a special screening of the Starz comedy and a panel discussion.
The series follows Walter Blunt (Stewart) as he moves to Los Angeles to host a nightly cable news show.