"I know in the beginning there's something she's kind of nervous about," Duhamel said, declining to divulge anything else about the band's performance Sunday.
The "Transformers" and "Life as We Know It" star joined other celebrities Saturday in DirecTV's Celebrity Beach Bowl, a flag football game on a sand-filled football field that was held inside a heated tent in downtown Dallas. Other celebrities included Chace Crawford of "Gossip Girl," Kevin Dillon of "Entourage" and Hayden Panettiere.
Duhamel said he'll be at Cowboys Stadium on Sunday to support his wife and her fellow band members. Fergie and Duhamel were married in January 2009, after dating since 2004.
At a news conference earlier this week, Fergie and fellow Black Eyed Peas members held back on discussing too many details about their performance during the game between the Pittsburgh Steelers and the Green Bay Packers.
"We're not allowed to give away the set list, but it will be packed with energy - what the Black Eyed Peas bring," Fergie said, adding that it was a "huge honor" to be picked as halftime performer.
"We want everybody to have a good time and just dance, party," band member will.i.am said.
The six-time Grammy award-winning Black Eyed Peas have sold more than 28 million albums worldwide and are known for songs such as "Boom Boom Pow," "I Gotta Feeling" and "Imma Be."
A person familiar with the plans for Sunday's halftime show said R&B star Usher and former Guns 'N Roses guitarist Slash are slated to make surprise appearances. The person spoke to The Associated Press on condition of anonymity Wednesday, because the musicians' performances were not going to be announced.