Which marketing strategies are used to advertise maybelline's products?

I'm doing a bit of research on marketing strategies, in particular, those which include celeb endorsement.

So I have picked Maybelline and Sarah michelle gellar (she was used by Maybelline in 2000).

What marketing strategies do you think Maybelline are using, I know at the time they were using Lintas ad agency but I can't find their methods anywhere.

The full title of my work is,

'Discuss how a celebrity product range is marketed, and how marketing strategies are used to sell these products.'

Any help would be wonderful!