I presume it is a painted ceiling in which case you need to paint it with 2 coats of sealant ( your diy shop will have these) then paint with the final paint colour of your choice
A suitable (and very cheap) sealant is PVA (or white wood glue). Brush it on diluted with water about 50/50. No point buying an expensive proprietary product which is expensively packaged PVA anyway.
I fully expected someone to have suggested stain block, which is horribly expensive for what it is.
I�ve just done something similar with advice from my painter/decorator (50 years in the trade, Dulux qualified etc) and he recommended using ordinary trade quality undercoat, just like you�d use on woodwork. Worked a treat. Emulsion over.
Would strongly recommend that you DON�T USE gloss.