The idiomatic expression "a lot of stars" means a large number or abundance of something. In this context, it refers to the many celebrities who attended the event and made an appearance.
Sentences with «lot of stars»
One way or the other, that is a whole lot of star power. (movieweb.com)
And, there are lots of stars in this sweeping view — over 100 million, with some of them in thousands of star clusters seen embedded in the disk. (sciencedaily.com)
Lots of all star appearances and scoring but thats it. (sbnation.com)