Amber Rose & Wiz Khalifa -- We're Burying the Hatchet, for the Sake of Our Kid

Amber Rose and Wiz Khalifa have called a truce in their custody war ... and they've agreed to co-parent their son ... TMZ has learned.

You'll recall Amber and Wiz were at each other's throats, each calling the other a horrible parent and unfit to care for their 2-year-old son Sebastian.

But a song changed Amber's tune. She heard Wiz's new song, "See You Again," which appears on the "Furious 7" soundtrack. We're told here's what got to her:

How could we not talk about family when family's all that we got?
Everything I went through you were standing there by my side
And now you gonna be with me for the last ride

Our sources say Wiz asked Amber to listen to the song, and after she heard it she tearfully called him back and they agreed to work as parents to care for Sebastian.

Baby steps.