New Jersey Gov. Chris Christie, who has both joked about his weight and said that it's a real concern, secretly underwent a weight-loss surgery in February that experts say could help him if he gets exercise and watches what he eats.

The father of four agreed to the surgery, in which a band was placed around his stomach to restrict the amount of food he can eat, after turning 50 in September, his spokesman confirmed on Tuesday. Christie told the New York Post, which first reported the surgery, that he wasn't motivated by thoughts of running for president.

"I've struggled with this issue for 20 years," he told the Post. "For me, this is about turning 50 and looking at my children and wanting to be there for them."

Christie has never disclosed his weight, but it's been an issue throughout his political career. In interviews with David Letterman, Oprah Winfrey, Barbara Walters and others, Christie has both joked about the issue and said solemnly that he's trying to shed pounds.

After an appearance on Letterman in February, he was asked repeatedly about his weight. At one point, he said he had a plan for shedding some pounds: "Whether it's successful or not," he said. "You'll all be able to notice."

Christie, who is running for re-election, declined to say how much weight he has lost since the surgery.

Concert news: Willie Nelson, Turtles

Fresh off celebrating his 80th birthday, Willie Nelson will play his first concert at the Minnesota Zoo's amphitheater on July 16 — one of the biggest and priciest gigs ever in the 21 years of the Music in the Zoo series. Tickets are $87-$99 and go on sale Friday at 10 a.m. at the Electric Fetus in Minneapolis and via Ticketmaster. A major outdoor concert event for fans one-fourth Willie's age, the Summer Set Music & Camping Festival also announced its second annual lineup Tuesday with Passion Pit, Girl Talk, Big Gigantic, Sound Tribe Sector 9, Big Boi, Doomtree and many more electronic and hip-hop acts. The fest takes place Aug. 9-11 at Somerset Amphitheater in Somerset, Wis. Three-day passes are now available for $100 via

While Nelson's joining the animals, the Minnesota State Fair Grandstand will feature the Cat Video Festival and Trampled by Turtles. The Duluth-bred bluegrass-folk group will headline the MN Music-on-a-Stick bill on Aug. 30, with Mason Jennings and the Chalice also appearing. The Turtles will return to the grandstand for the third consecutive year on Aug. 26 for their Happy Together Tour, featuring Chuck Negron of 3 Dog Night, Gary Puckett, Gary Lewis & the Playboys and Mark Lindsay. A trio of "Saturday Night Live" alums — Dana Carvey, Dennis Miller and Kevin Nealon — will kick off the grandstand series on Aug. 22. Tickets for all three shows will go on sale May 18. For more information, go to

Staff and wire reports