10/24/2011 at 05:00 PM EDT
Before her weekend concert, Jennifer Lopez
showed no hint of the emotions
that would be displayed on stage.
"I was watching her in the dress rehearsal and she was just giddy and having so much fun," Maria Menounos, who spent time with Lopez, 42, tells PEOPLE. "She seemed really positive and upbeat."
But when Lopez saw her mom in the audience during a performance of "Until It Beats No More," she suddenly broke down, she tells Menounos, 33, in an interview airing on Extra
"I didn't see her the whole time until this one moment, and I was a bit emotional," the singer explains in the interview.
As for having dancers re-enact scenes with some of the men from her past, Lopez tells Extra
she "wanted to do a section of the show that talked about love [and] different moments in my life."
Lopez, who calls herself "a regular person like everybody else," adds, "I have feelings and emotions. My life goes great and it goes not great sometimes. But you know what? We keep going, and that’s what it is."