Brisbane Roar midfielder Charlie Miller says he is relaxed about facing old enemy Celtic on Sunday.

The 33-year old playmaker spent the first six or so years of his professional career with Rangers in Scotland and admits he used to get worked up before every Celtic clash.

Now he has matured and Miller is looking forward to enjoying the opportunity to play against his old foes.

"The days we played at Rangers it was great to beat them, so I definitely want to beat them this weekend as well," Miller said.

"When I was younger, I would be nervous and really wanting to win.

"I'm a bit older now. I'm just going to look forward to it.

"A hundred per cent I want to win this game. I never like to lose against Celtic, but I'm glad they're coming over. It's great to see them here and it'll be a great match."