Fetty Wap Surprises GF at Fashion Show with $100k Investment

Don't tell Fetty Wap ya can't mix business with pleasure ... because doing just that put a huge grin on his girlfriend's face.

The rapper surprised his girl, Yaya, Sunday at her Omaj by NoiR clothing line launch party in Ridgefield Park, NJ. The outerwear collection is slated for a spring release but friends and family got a preview along with a $100k surprise from Fetty.

He proudly announced he's sinking that chunk o' change into her biz ... after he performed and walked the runway for her.

"Love & Hip Hop: New York" star Mariahlynn hosted the event, but Fetty definitely stole the show.