Sealing Emulsion in shower area

[RJE]

I have created a wet room which has a low ceiling and angled sloping wall, which will be prone to splashing when the shower is in use. The ceiling is plasterboard with plaster skim, and then painted with emulsion.
I want to seal the wall and ceiling over the top of the emulsion with a clear waterproof sealant that will bond with the emulsion. Has anybody any idea if this product exists?

 

[joe-90]

Why not paint it with bathroom paint? Emulsion doesn't look like emulsion when given a clear coat anyway.

 

[Dulux]

I'd use eggshell.