The couple was supposed to catch a flight out Friday night, but ended up driving instead after missing it.
"They didn't arrive until 3 a.m. Saturday morning," a source tells E! News. Once they got to Vegas, they headed to their two-bedroom suite at the Palazzo, where they were joined by Megan's sister and her boyfriend.
After a quiet Saturday at the suite, they did some shopping on Sunday. Then the group had a late lunch at Dos Caminos Mexican restaurant, ordering ceviche along with chicken and steak tacos.
Later, it was on to catch Mystère by Cirque du Soleil at Treasure Island. After the show, the group declined to meet the cast and instead headed to a late dinner at Red Square. So is Megan is off the market again?
"They're definitely together...100 percent!" says a source of the twosome.
The group didn't do any gambling while in Vegas...but when your movie makes $201 million at the box office on opening weekend, who needs to hit the tables?