GUY: ...John Cleese?!
CLEESE: Yes, hello, who is this?
GUY: Um, I'm [name1]... I was trying to reach [name2]...
CLEESE: Ah, I see the problem. You see, I'm a client of his, and this phone number is for private business between us. He must have given it to you by mistake.
GUY: Oh, I see... um, I'm a big fan of yours, Mr. Cleese...
CLEESE: Oh, are you really! I suppose you'd like me to do a silly walk or something. Well, look! I'm doing one right now! Can't you tell?
GUY: Er... sorry to bother you, Mr. Cleese.
CLEESE: Quite all right, quite all right. But could you do me two favors, please?
GUY: Sure, what?
CLEESE: First, don't call this number again, and please do not give it to anyone else.
GUY: I promise I won't.
CLEESE: Good lad. And second... I want you to get a job with this company, rise to the top levels of management, and fire the silly sod who gave you this number, would you?
GUY: Heh. Okay!
CLEESE: Buh-bye now!
The sketch was less coherent than this in the dream, of course; I tidied it up in editing after I woke up.