Disguising join between wall tiles and ceiling
 

W are decorating our bathroom and have had the ceiling replastered smooth with sunken spotlights. The ceiling has now been painted white but there is a noticeable join between the floor to ceiling wall tiles and the final grout layer before the ceiling. The grout is dark rather than white so is very noticeable. I am looking for ideas to minimise the appearance of the join. Coving? painting the grout? any other ideas?

I have a friend that is a professional tiler. He had helped me on a couple jobs. I will always remember what he had told me "I doubt caulk it out" I don't know how large you gap is but If 1/4" or so I don't see why you couldn't use a good latex modified type caulk of what ever color you see fit ceiling color or grout color. The 100% silicone caulks are harder to use. The latex modified or latex silconized can be cleaned with water and shaped with a damp rag or finger for a cleaner look.