Telles joined the Red Devils from Porto before the transfer deadline slammed shut.
He knows Fernandes from their time in Portugal, with the latter playing for Sporting CP before coming to England.
And the two spoke about the United players Telles will soon meet and play with.
Telles told the club website: "I believe I'm going to meet a marvellous group. I've spoken to Bruno Fernandes and he's said how welcoming the boys are.
"I believe I will settle very well into the group."