Happy Birthday, Thomas Hayward. Unfortunately he's dead, he would have been 177 today. Only a year younger than me.

The line is a piece of deadpan, self-deprecating humor typical of Cleese: it begins with a seemingly earnest commemorative greeting, then undercuts it by noting the honoree is long dead. The punchline pivots to absurd exaggeration—claiming Cleese is only a year older than someone who would be 177—mocking celebrity birthday tributes and the performative solemnity of public remembrance. It also plays on the incongruity between historical time and present-day social media habits, where people address the dead as if they were contemporaries. The joke’s structure relies on escalating incongruity: respectful → morbidly factual → wildly impossible.