Hugh Jackman is mourning the loss of his long-time “X-Men” co-star and friend Patrick Stewart, who died on Wednesday at age 86 after a “brief battle” with Alzheimer’s and Lewy Body Dementia.

“We lost one of the greats of stage and screen today,” Jackman wrote on Instagram. “And, in my book, a tremendous friend and man. I learned so much from him. I will miss you, Patrick Stewart, all of my days.”

Jackman and Stewart memorably portrayed Wolverine and Professor Charles Xavier in several “X-Men” movies, including 2000’s “X-Men,” 2006’s “X-Men: The Last Stand,” 2009’s “X-Men Origins: Wolverine,” 2013’s “The Wolverine” and 2017’s “Logan.” Stewart also appeared in Marvel’s 2022 sequel “Doctor Strange in the Multiverse of Madness,” and he will reprise his role in this December’s “Avengers: Doomsday” alongside his good friend Ian McKellen as Magneto. It’s unclear if Wolverine will return for the superhero sequel.

“Hugh and I were so thrilled when the last thing we did for ‘X-Men’ was ‘Logan,’” Stewart told Variety in 2020. “It was the best ‘X-Men’ experience we both had, because we were the same characters but their world had been blown apart.”

Jackman was among the many bold-face names who paid tribute to Stewart, whose 60-year career included such noteworthy roles as Captain Jean-Luc Picard on “Star Trek.” Kevin Feige, the president of Marvel Studios, described the legendary actor as “brilliant, charming, warm, generous, with a quiet strength and gravitas.” William Shatner, his fellow USS Enterprise captain on “Star Trek,” praised the “brought intelligence, grace, and a deep sense of humanity to everything he did.”