The 90-second advert sees John, 73, send up his flamboyant reputation, while Caine mocks himself by repeating the famous catchphrase used by his innumerable impersonators: "Not many people know that".
The commercial, released on Wednesday (February 10), features John pretending to audition for the role in the advert, and receive criticism from the director for his acting skills and for being too "showbiz", before the singer delivers an impression of Caine himself.
After pretending to have a vaccine shot, he bursts into a rendition of "I'm Still Standing" - one of his hit songs -whereupon the director quips: "Thanks Elton, we will let you know".
"Hello, my name is Michael Caine," the 87-year-old actor says. "I've just had a vaccine for COVID. It didn't hurt - not many people know that."
The director thanks Caine, before adding: "Let the little fellow know he didn't get the job".
Britain has currently delivered first doses of vaccine to more than 12.6 million people and is on course to reach its target of reaching 15 million in the top four priority groups, including those aged over 70, by February 15.