The iHeart Radio Music Festival offered plenty of surprises, but nothing compared to the surprise audiences received on Saturday night (Sept. 22). Midway through Mary J. Blige's set, Prince was brought out onstage for a two-song medley.

The 12,000 concertgoers at Las Vegas' MGM Grand went ballistic as the Purple One graced the stage with his newly-coiffed Afro. Prince was wearing a black printed shirt, yellow pants and boots with a guitar that matched his entire outfit (talk about being fashion coordinated). But the one thing that really stood out? The futuristic-looking gold sunglasses that covered his eyes and forehead.

According to Yahoo! Music, Prince initially stayed quiet and plucked his guitar during MJB's performance of Chaka Khan's 'Sweet Thing.' Then Prince obliged (excuse the pun) the Queen of Hip-Hop Soul with one more song. "Sing with me tonight," she pleaded. "I know you have to be very particular about who you be messing with."

The duo agreed to perform 'Nothing Compares 2 U,' a Prince-penned song that became a chart-topping hit song for Sinead O'Connor in 1990. Their soulful performance mesmerized the audience and if you watch the video above, it will certainly give you goosebumps. Prince then asked the crowd, "Y'all mind if I play this thing," before taking center stage and rocking out a guitar solo like a scene from his classic 1984 flick 'Purple Rain.'

Afterward, Mary J. Blige bowed and thanked Prince for his appearance. But the party didn't stop there -- the veteran singer got the crowd even more hyped with an energetic performance of 'Just Fine.'

All and all, Mary J. Blige and Prince's performance was, undoubtedly, one of the top highlights at the iHeart Radio Music Festival. As fans in attendance can attest, the festival was spectacular. "I had the absolute BEST time tonight!! #iHeartRadio festival was amazing!" wrote one concertgoer, while another tweeted, "My ears are ringing from #iHeartRadio best concert ever!"