Walls and Ceilings - Mis-Aligned Drywall

Hello DIYers and pros alike. Quick question if I may, I was unable to find an answer searching the boards.

I have a 10' x 9' room in my basement whos ceiling isnt perfectly level. Im currently drywalling the room and have come across this situation. When hanging a piece of drywall on one of the 10' wall lengths, attempting to butt the drywall against the ceiling drywall (I've believe this is suggested for additional support) I end up with a 1/2" gap at one end of the wall where the wall board meets the ceiling. The gap goes from 0" to a 1/2" through about a 6' length.

My question is this. Can this 0" to 1/2" gap be fixed during the mudding process? If so should some sort of corner bead material be used? If I need to re-do the wall (prefer not to but...) whats the best practice for placing drywall on a wall where the ceiling has a slight slope?

Many thanks for your time.

I went ahead and hung the drywall.

I then used a quick setting mud (in the bag) and used that to fill all the gaps prior to taping.

I used the quick set for a couple of reasons. I think it is harder and it is supposed to shrink less.

After I got the gaps filled and the mud dried, I then taped normally.

I assume you have some backing to put the mud against...

Thanks for your input rdhamm, I'm a bit relieved to hear your response as it confirms what I had hoped I could do. Also appreciate the tip on the quick set. As far as a backing goes, I have vapour barrier in behind that could act as a bit of a backing but I still have access on the back side of the wall so I think I'll tack something up there thats got some strength.

As long as the rock is securely mounted there is nothing wrong with having gaps that need prefilling. As long as the rock is hung in a manner that alows proper finishing it doesn't matter if there are gaps here and there that need prefilling. Good finishing will hide all the little imperfections.