Jeezy Ditches Las Vegas Gig for Surprise Jay-Z Performance

Jeezy was supposed to perform in Las Vegas on Sunday night, and when he finally took the stage, he was across the country at Yankee Stadium ... and it's all because of Jay-Z.

The rapper pulled the plug on his scheduled residency performance at PH Live inside Planet Hollywood ... opting instead for a surprise cross-country trip to New York City, where he reunited with Jay during the legend's star-studded "Extra Innings" concert.

Folks back in Vegas were wondering why Jeezy's show was abruptly canceled ... and they got their answer late Sunday when the Snowman emerged onstage alongside Hov to perform their longtime collaborations "Seen It All" and "Go Crazy" ... sending the Bronx crowd into a frenzy.

The cameo was just one of many massive surprises during Jay-Z's grand finale, which capped off his historic three-night Yankee Stadium residency celebrating the anniversaries of "Reasonable Doubt" and "The Blueprint."

Night 3 turned into a who's who of hip hop and R&B ... with appearances from Beyoncé, Rihanna, Clipse, Pharrell, Usher, Swizz Beatz, Teyana Taylor, Jermaine Dupri, The-Dream and more joining the festivities.

The concert itself was delayed for hours after security issues outside the stadium forced organizers to temporarily halt entry ... but once Jay-Z finally took the stage, he delivered a marathon performance packed with surprise guests and career-spanning hits.