Britney Spears Wraps Circus Tour in U.S.
09/28/2009 AT 06:30 AM EDT
"Hey Vegas, how y'all feeling?" the headliner, 27, asked the crowd in one of the only times that she spoke during the 90-minute show at Mandalay Bay also attended by Lance Bass and Barry Manilow.
Bass didn't stay in his seat for the entire show, though: He was given a brief lap dance by Spears during the song "Breathe on Me," in which an audience member is invited on stage. Bass was seen singing as Spears smiled at him during the sexually charged choreography.
Sunday's show was the second of Spears's Vegas concerts over the weekend. On Saturday, Miley Cyrus and Spice Girl Melanie Brown attended the concert.
It wasn't all work for Spears in Vegas. Sunday afternoon, the pop star was spotted at Mirage's Sugar Factory with sons Sean Preston, 3, Jayden James, 2, and beau Jason Trawick.
"She spent about $3,000 and walked out of the store with 10 bags," a source tells PEOPLE. "She got a bunch of candy and shirts for her kids and got a bunch of the couture lollipops to give to her backup dancers." Following the purchase, the store sent another $2,500 in merchandise to her room at the Mirage Villas, according to the source.
Though she is finished with the United States leg of the tour, Spears is set to play several shows in Australia in November.