Ariana Madix opened up her wallet big time to help out a friend of the 'Vanderpump Rules' family ... this after a major health scare that's threatening their life.
AM was among several 'VP' stars to draw attention to the GoFundMe page of Jesse Montana -- who's a pal of theirs and who's appeared on the reality show. He recently revealed he's been diagnosed with a brain tumor, and he's looking to raise funds for his hospital stay ... 'cause he's going into surgery on Monday.
Like we said ... a lot of the 'Vanderpump' cast members have donated, but Ariana has shelled out the most by far -- offering up a $9,000 donation to help Jesse.
In hopes that Jesse's unexpected health woes don't leave him with a financial burden, the GFM page has a goal to raise $100,000.
The cast began donating over the weekend ... and other 'VPR' contributions include Katie Maloney giving $3,000, Scheana Shay dropping $2,000, Tom Schwartz and Rachel Leviss chipped in $500.
'VPR' alums Brittany Cartwright and Kristen Doute donated $100 and the show's executive producer, Alex Baskin gave $250. The donations touched Jesse ... who said in his IG Stories ahead of surgery Monday that he'll "forever be shocked at how fast life can change."
He thanked his Pump Rules family, his parents, boyfriend Joseph Newham, his doctors and everyone who supported him ... adding: "I'll be dreaming of you in colors that don't exist during surgery, cya on the other side angels."