I am a master's student and I started searching for someone to be my thesis advisor. I went to ask a well-known professor from my university, that I wanted to work with, and he was happy to help.
However, he said that his and my area of interest at the moment don't align. But, he did say that he has a good friend in the US who does exactly what I am interested in and has set up a meeting between us two.
My professor said that I should ask him whether he would be willing to co-advise my master's thesis however, I am not sure whats the best way to ask this question.