Britney's Family Circus

Just a few hours before taking the stage at the American Airlines Arena in Miami, Britney Spears seemed nothing like the erotic pop star that she portrays in her new tour. Instead, the real-life mom showed her nurturing side by bringing joy to dozens of ill youngsters at Miami Children’s Hospital on March 7.

The scene brought tears to many of the parents present – and spoke volumes about the new Britney.

“This tour has had a totally unexpected impact on Britney and her own kids, turning them into a real family,” a friend of Britney tells OK!. “At first, Preston and Jayden were set to stay home with dad Kevin Federline, but as the start date came closer, the boys begged their mother not to leave them.”

Initially, Britney struggled with the idea of adding parenting responsibilities to an already grueling performance schedule.

“She worried, ‘Can I handle it?’ ” her pal reveals. “But it’s working out better than
anyone could have predicted.”

Britney expanded The Circus convoy with one extra bus, which sons Preston, 3, and Jayden, 2, share with their father, Kevin.

“Even though Britney is working harder than she has in years, she’s also spending more time with the kids than she has in their entire lives,” her friend tells OK!. “Britney is finally a grown-up who is taking being a parent seriously.”

But 27-year-old Britney still loves having fun with the boys! On March 5, she treated her sons to a day at Walt Disney World. “Preston and Jayden were so excited,” a park guest tells OK!. “They wanted to meet Mickey right away.”

And on Wednesday night, Britney got a surprise visit from someone almost as famous as Mickey Mouse — Madonna!

According to Britney's personal site, the Material made a surprise appearance at Brit's show in Long Island, NY. "Britney was thrilled to have her there!" reads a statement on the site.

For more on Britney's family life on the road, pick up the new issue of OK!, on sale everywhere!