Cut a sheet of drywall to size to fit the curve of the wall. Install the drywall, with drywall screws, to a stud on one edge of the curve. Install a piece of 1x2 on the drywall, sandwiching it between the stud and the 1x2.
Spray the drywall on both sides, at the place where it needs to bend. Use a spray bottle with water. Push very carefully on the drywall to bend it to the wall.
Screw the drywall to the next stud every 6 inches. Continue spraying and bending until the drywall is fully installed. Remove the 1x2 strip.