Chris Brown -- Jetting to Haiti w/ Andre Berto ... We're Here to Help!

Chris Brown just jumped on a private jet destined for Haiti ... but it's no vacation -- we're told he's putting on a free concert to help out the locals ... and it's all thanks to boxer Andre Berto.

Berto and Brown have been friends for a while and Andre -- a Haitian American -- is passionate about the current crisis between Haiti and the Dominican Republic.

FYI -- The D.R. is currently cracking down on Haitian migrant workers living in the Dominican, deporting them by the thousands ... and the Haitian Prime Minister called it a "humanitarian crisis" because many of those people don't know where they're going to live, work, etc.

So Berto asked Brown if he would fly to Haiti to put on a concert to lift the people's spirits -- and Brown obliged.

We're told the crew is on the jet right now.