Blocking off and internal Archway with Drywall

[LGWIZZ]

Hi.

Hope you are all well. After for some advice please on blocking up this archway in the pics.
I'm happy with the studwork and plasterboard. My question is how do I drywall to the existing plaster please?

I want to try and avoid plastering the entire wall.

 

[Tigercubrider]

That looks as if either it’s been knocked through a brick wall, or has been a doorway that has been modified to an arch?

As far as I can see, the wall is brick and the wall reveal could be artex. Get it tested.
You’d need to create a wall plate on both sides, 15-20 mm from the line of the wall.
Then follow the shape of the arch, obviously easier by making straight boxes as much as possible.
If there are likely to be kitchen cupboards on one side, add mounting studs at the correct height.
Fix through to the brick

I would fill it with rockwool.
Have a plaster skim a decent amount of undercoat before finishing with a skim. It would look better if the skim goes onto the existing walls.

 

[foxhole]

You just infilling arch, not doorway?

 

[LGWIZZ]

@foxhole arch and doorway. Apologies