The Odd Couple star landed his big break opposite Henry Fonda in the 1957 film adaptation of 12 Angry Men, playing Juror 5, and he was due to tackle the courthouse drama again - as wise Juror 9 - during a month-long run at New Jersey's George Street Playhouse.
But Klugman, who turns 90 next month (Apr12), has bowed out of the production so he can remain close to his Los Angeles personal physician.
All My Children star David Canary will step in to replace the actor when the play opens on Tuesday (13Mar12).
Director David Saint tells Playbill.com, "Jack's spirit in the rehearsal room has been an inspiration to the entire cast and me. While I am saddened at the thought of not having him in this cast, his health is paramount.
"We send him every good wish for a speedy and complete recovery. David is an amazing actor, and with his daytime television experience, is used to working quickly. We are fortunate to have him."