Bannan jumped through Hoops to defend the Bulgarian midfielder during his tough introduction to English football after seen him at his best.
Petrov has returned the favour by keeping a watchful eye on Bannan since the Scottish under-21 international's parents returned north of the border.
Bannan told the Sunday Mercury: "I'm really friendly with Stiliyan.
"He'll phone me because I'm on my own now, so I'm not alone. He's good that way, he's brilliant.
"Obviously Stan was unbelievable in Scotland and he was my hero when I was younger. Now training with him and talking to him is so strange, but he was like my idol at Celtic."