NEW YORK -- CBS apologized on Sunday for an unexpectedly R-rated end to its Super Bowl halftime show, when singer Justin Timberlake tore off part of Janet Jackson's top, exposing her breast.

"CBS deeply regrets the incident," spokeswoman LeslieAnne Wade said after the network received several calls about the show.

The two singers were performing a flirtatious duet to end the halftime show, and at the song's finish, Timberlake reached across Jackson's leather gladiator outfit and pulled off the covering to her right breast.

The network quickly cut away from the shot, and did not mention the incident on the air.

Timberlake said he did not intend to expose Jackson's breast.

"I am sorry that anyone was offended by the wardrobe malfunction during the halftime performance of the Super Bowl," Timberlake said in a statement. "It was not intentional and is regrettable."

Wade said CBS officials attended rehearsals of the halftime show all week, "and there was no indication any such thing would happen. The moment did not conform to CBS' broadcast standards and we would like to apologize to anyone who was offended."

The Super Bowl halftime show, which also featured Puff Daddy, Nelly and Kid Rock, was produced by MTV, CBS' corporate cousin in Viacom.

"We were extremely disappointed by elements of the MTV-produced halftime show," Joe Browne, NFL executive vice president, said. "They were totally inconsistent with assurances our office was given about the content of the show.

"It's unlikely that MTV will produce another Super Bowl halftime."

MTV issued a contrite statement in which it also apologized, saying the incident was "unrehearsed, unplanned, completely unintentional and was inconsistent with assurances we had about the content of the performance."