Old inglenook fireplace meets plasterboard

[Jennifer smith]

Hi,
Hoping for some insight or suggestions.
We opened up this massive fireplace and will have an large oak mantel and 4 foot wide wood side legs. That was the easy part.
We pulled down all walls to insulate except on the fireplace walls bc it would have brought it out too far.
Question is how do you skim the side wall and finish it off nicely to the stone?
Thank you

20210430_131315

• Jennifer smith
• 26 Jul 2021

Fireplace dining room

IMG-20210726-WA0006

• Jennifer smith
• 26 Jul 2021

Gap

 

[Deleted member 267285]

I’m no expert, but, perhaps plasterboard it, then apply another board to the upper (aka double board), and then skim?