The Dons were drawn against the holders and favourites for February's fifth round 24 hours after Neil Lennon's side beat Hearts 7-0 in the fourth round.
Reynolds, whose team bounced back from consecutive 3-1 defeats against Hearts and Celtic, said: "It's probably the toughest draw in the hat. You look at the last round and they absolutely annihilated Hearts and we know Celtic are capable of doing that.
"But on the other hand we went down there the other week and played well for 90 minutes. It was the last three minutes of extra time that cost us the game.
"We won't go there with any fear. If you're going to win a cup you need to beat Celtic at some point so why not this round?"