Is there such a thing as too many celebrities in a movie?

A recent trailer for the movie 'New Year's Eve' has me wondering whether movies are ever any good when they have a number of well known actors/actresses in them. Looking into a few examples, I've found that movies with a good plot and a number of celebrities work e.g. Love Actually, whilst movies with a number of celebrities and individual plot lines melding into one , do not e.g. 'Valentine's Day' and 'He's Just Not That into You'. I will be interested to see how the box office does with 'New Year's Eve' and to know what your opinions are.