Keke Palmer Cries While Explaining Why Hollywood's Hard

Keke Palmer gave a teary explanation of the hardest part of being in Hollywood ... all while plugging her new book oh so perfectly.

Keke was at the Grove's Barnes & Noble Saturday doing a book signing ... when someone asked her about the struggles of being famous.

She lets it all hang out here. Also worth noting ... her book title, in part, is "Quiet the Noise and Find Your Voice." Gotcha ...