Marky Mark is back?! Mark Wahlberg surprises crowd at New Kids on the Block concert!
It was double the Wahlbergs at New York City's Madison Square Garden on Monday night!
Mark Wahlberg -- formerly known as Marky Mark -- surprised thousands of fans at the New Kids on the Block show when he showed up during his brother Donnie Wahlberg's performance of "Good Vibrations."
This was the first time the Ted 2 star has joined his brother's boy band on stage in over 20 years.
See the Wahlberg brothers through the years:
WATCH: New Kids on the Block -- Then and Now
And he wasn't the only surprise star of the night! Rapper 50 Cent introduced Mark to the excited audience, exclaiming that it looked like there were some "good vibrations here tonight."
A post shared by New Kids On The Block (@nkotb) on Jun 22, 2015 at 4:42am PDT
The 39-year-old hip-hop star was also joined by Biz Markie. The rappers performed their hits "Just a Friend" and "In Da Club."
PHOTOS: New Kids on the Block Flaunt Their Abs on Instagram
NKOTB's Main Event tour has been thrilling fans across the country since they first kicked off their 40-concert series in Las Vegas on May 1. They were also joined by '90s chart-toppers TLC and rapper Nelly.
ET was there during their tour rehearsals. Check it out:
