You'll recall at the start of this pandemic, stories about celebrity cases of COVID were pretty common, so it's nice to now have stories about celebrity vaccinations against COVID.
What's more, if you can get an advertisement for health services out of it, then all the better. In this case, you've got two icons - Elton John and Michael Caine - auditioning for an advertisement about vaccination.
The ad does however appear to be suggesting that if the audition process doesn't go just the way they'd like, they don't get the jab. To be fair, Michael Caine is an experienced actor of several decades while Elton John's only just recently gotten in on the act with 'Kingsman 2: The Golden Circle' and so on.
You'd hardly put a piano in front of Michael Caine and ask him to sing 'Goodbye Yellow Brick Road' or 'Honky Cat' and expect it to be good, right? Maybe it could be, though. We don't necessarily know if Michael Caine is an accomplished pianist and singer.
Anyway, here's the advertisement.
— NHS England and NHS Improvement (@NHSEngland) February 10, 2021