The National Football League says it will be the most entertainment-packed Super Bowl ever, with performances by U2, Paul McCartney, Mariah Carey, Mary J. Blige, Marc Anthony, the Boston Pops and others – not just on Super Bowl Sunday, but throughout the weekend.

Part of the reason for the celebrity overflow is a patriotic theme after the September 11 terrorist attacks, which caused the Super Bowl to be pushed back a week.

“With the events of September 11th, we’ve redefined and refocused the game presentation, and the theme is celebration of the human spirit and the values of freedom, and also to everyday heroes,” said NFL spokesman Brian McCarthy.

“And with that in mind, we sought out the entertainment community. They sought us out as well.”

McCartney is expected to sing his September 11-inspired song “Freedom” during the pre-game show, which will also feature Barry Manilow singing “Let Freedom Ring” with Patti LaBelle, Wynonna and others.

Carey will sing the national anthem and Blige and Anthony will sing “America the Beautiful,” all of them backed by the Boston Pops. U2 is to provide the half-time entertainment, singing three songs, including the inspirational “Walk On.”

“Can you imagine what it feels like to be Irish and be at the most American of occasions? It’s most overwhelming,” said Bono, U2’s lead singer, at a news conference in New Orleans on Wednesday.

“We’ve had an incredible year in America,” he said. “And post September 11, to have our album mean so much to people who are not U2 fans is very special to me.”

Besides patriotism, the strong star presence also reflects a growing trend at major sporting events toward partnering music with sports to boost the ratings and broaden the audience of both.

Last year’s Super Bowl half-time show featured Aerosmith, *NSYNC, Britney Spears, Nelly and Blige in an MTV-produced extravaganza. At the NBA Finals last year, Destiny’s Child, U2 and Sugar Ray performed during half time.

“Musical acts, including those that we have this year, do help hold the audience during the pregame and also during half time,” McCarthy said.

Gregg Winik, executive vice president of NBA entertainment, said tying chart-topping performers to the games helps bring in fringe fans.

As they did last year, Super Bowl musical performances this weekend will actually kick off on Friday, with No Doubt, Ja Rule, Martina McBride and others performing on a CBS special. No Doubt and the Barenaked Ladies are also performing on a Fox tail-gate special before the pre-game show.

Elton John is to perform at the NBA All-Star game on Feb. 10. That weekend will also include performances by Britney Spears, Sean “P. Diddy” Combs and Alicia Keys.

Entertainment has always been part of the Super Bowl. In its early decades, in the 1960s, ’70s and even ’80s, that mainly meant performers such as Up With People, cartoon characters or the Rockettes. It wasn’t until Michael Jackson’s ratings-grabbing performance at the 1993 half-time show that A-list performers started taking notice.

“That was the turning point in securing major entertainment stars to perform,” McCarthy said, adding that the potentially huge audience was a powerful lure to musicians. The Super Bowl is generally seen by an average of 90 million viewers in the United States.

“It was a very easy pitch to U2’s management,” he said. Although Blige is a platinum-selling artist, she sounded almost grateful to be involved in the Super Bowl for a second year. “There’s a lot of people who don’t know who Mary J. Blige is, and that’s why I’m so thankful,” she said. “They’re helping me to be introduced into another world, another group of people.”