Actor Stacy Keach is on the mend and sounded full of spirit during a phone chat on Thursday.

Released from Northwestern Memorial Hospital on Wednesday, he is back in his temporary Chicago “home” (at the Langham Hotel) and recuperating from the “mild” heart attack that forced him to leave the stage on the opening night last week of “Pamplona,” the new one-man show about Ernest Hemingway’s later years that was set to run at the Goodman Theatre through June 25. The show was cancelled after Keach took ill.

“I just wish I could go back to the theater tonight and perform the show,” he said. “But I hope we can bring it back to Chicago next year.”

Keach is recuperating under the watchful eyes of his wife, Malgosia Tomassi, and his daughter.

He admitted “the synchronicity between my losing my way up there on stage, and Hemingway’s writer’s block, which was perhaps the result of all his concussions, cannot be denied. . . . Nothing  like that had ever happened before in my long career, and it was the actor’s nightmare.”

He laughed at the suggestion that he had taken “method acting” just a step too far.

“I didn’t have pain, just a feeling of being in a fog,” he recalled. “And I went to the window on the set to get a prompt, but just couldn’t get back on track. I felt OK when I first went out on stage.”

At Northwestern, where he was under the care of Dr. Clyde Yancy and Dr. S. Chris Malaisrie, Keach underwent a surgical procedure. He will spend the next couple of months doing rehab — walking and other exercises — and paying attention to his diet.

“I’m a good patient, but an impatient one,” the actor confessed, saying he is spending time with the “Pamplona” script and “watching TV news — the never-ending soap opera of what is going on in our world.”

As for the euphoria some heart attack patients experience with recovery, Keach said: “Well, I definitely feel better than I did last week.”

Stacy Keach as Ernest Hemingway in “Pamplona,” the one-man show by Jim McGrath that was canceled after the actor suffered a “mild” heart attack while performing on opening night at the Goodman Theatre on May 30. | Liz Lauren photo