Hi.
Much depends on thy type of paper, and how the plasterboard was treated before it was papered.
It would be expected that the board was coated with a primer, if so it shouldn't be damaged by the moisture involved by the paper removal. Some papers are more absorbent than others, making them easier to remove.
The traditional method of removal was to apply water with a brush, and allow to soak before removal with a stripping knife. These days a steam stripper is commonly used, but great care has to be used not to damage the board surface. So I'm a bit reluctant to advise the use of one on an unknown surface.
I suggest in this case to try a small area with just water, and experiment a little. there are chemicals that added to water help the water soak in. One is called DIF made by Zinsser.
Just make sure you leave the water plenty of time to soak in, The less you have to scrape, the less likely to cause damage.
When you have got the paper off, and the surface is nice and clean and smooth, apply a coat of Gardz, again made by Zinsser. this will seal back any residue of wallpaper paste, that could cause a lot of problems with the new paint.