Plummer was lined up to perform in the Shakespeare play in 1956 - but an unplanned romp left him unable to take to the stage, according to New York gossip column PageSix.
He says in his autobiography In Spite Of Myself: "I woke up alone the next morning... (pain) all around my groin and lower abdomen... I started to whimper like a whipped dog. 'So this is what syphilis is like?' I thought. 'I suppose I deserve it, but Christ, how the hell was I to know?'
But instead of being struck down by the disease, Plummer had dislodged a kidney stone and had to undergo a medical procedure with a surgical wire to resolve the problem.
He adds, "It began to sink in... Shatner, my understudy, would have to go on... (It) instantly brought back the pain. I screamed for a nurse who jabbed me with more morphine.
"I knew then that the Sob (son of a b**ch) was going to be a 'star.'"