He absolutely is famous enough to be recognisable on the phone. That's why I'm mentioning it. It is weird indeed. But kinda plausible, I can believe that. Did it never occur to you to meet someone you work with outside of your job and not recognize them before they greet you, just because they are wearing different clothes and you didn't expect to meet them here? It sure ocurred to me. Also, I remember calling my grandma as a kid to tell we'll visit her today (she was delighted to hear that!) and only after putting the phone down realizing that I actually called the wrong number (you had to enter the number manually back then).

I mean, people do make mistakes. And this was very convincing portrayal of a clumsy dude who is prone to making such mistakes. Very realistic fool.