Milk Tyson -- Celeb Weed Dealer ... Turnin' Over New Leaf

Celebrity weed mogul Milk Tyson has a new way of getting high ... charity.

Tyson owned a weed delivery company that catered to big, big Hollywood celebs. He got really famous after tattooing the face of one of his close party friends -- Justin Bieber -- on his arm.

There was a turning point in Milk's life when he and Justin sold some of the Biebs' spray paint cans and auctioned them off to benefit typhoon victims in the Philippines.

We found out Milk is hooked ... on charity. He sold his weed company and launched an 11-city hospital tour where he recruits celebs who record videos for children fighting serious illnesses.

Zendaya, Travis Barker and a bunch of other celebs have joined forces with Milk and the tour is already viewed as a big success.

Tyson's foundation, FAM -- Fighting All Monsters While Finding All Meaning -- expects to raise millions of bucks with the help of his celeb friends.

Now that's some really good s**t.