Accepted by a different proposed supervsior: writing a thank you letter This is a usual how to write a thank you letter but the twist is during the application process I put down professor X as a possible supervisor. I then interviewed with professor X and professor Y (both at the same institution). I was later accepted and the letter stated the supervisor would be professor Y. (Speculation: maybe professor X could not/did not want to take me on for whatever reason but professor Y did.) I spent a few days looking into professor Y's research and would probably accept. 

How do I go about replying to the offer and emailing both professors? I'm not sure how to navigate this situation with the expected tact. Any guidance would be appreciated. 

Context: this is for a PhD at a UK/European university.
All it really takes is something simple. 


  Thank you both for considering my candidacy. I'm happy to join the program under Professor Y's direction.  


And stay friendly with everyone.