Here's why Blac Chyna will join Amber Rose's Slutwalk this year

Blac Chyna's going to be marching with her friend, Amber Rose, at her annual SlutWalk ... and it's a direct shot at her ex, Rob Kardashian.
Sources close to Chyna tell TMZ ... she's joining the march to speak out against revenge porn and talk about what she's gone through since Rob plastered her nude pics all over social media in July.



We're told she'll have her lawyers -- Lisa Bloom and Walter Mosley -- by her side, and they're planning to speak to the SlutWalk marchers to educate them on how to handle being victims of revenge porn.

Blac wants 7 figures from Rob to settle the revenge porn case, amid their ongoing custody war.
The 3rd Annual Amber Rose SlutWalk takes place Sunday in Downtown L.A