When Bill Belichick appeared on ABC’s “Good Morning America” last week to promote his new book, “The Art of Winning,” the most revealing moment of the interview had nothing to do with his storied N.F.L. coaching career or his new job leading the University of North Carolina at Chapel Hill’s football program.

In fact, it was not about Mr. Belichick or his book at all. It was about the 73-year-old football coach’s 24-year-old girlfriend.

“A lot has been made about your relationship with Jordon Hudson,” said the host, Michael Strahan, himself a former N.F.L. star. “It’s been getting a lot of attention.”

Then he paused to note: “She isn’t here this morning.”

In the five months since the University of North Carolina announced it had hired Mr. Belichick as its new head football coach, giving him a five-year-contract that could be worth more than $50 million, Ms. Hudson has been there, standing not behind her man, but more often next to him — if not in front.

She was at the U.N.C. news conference announcing Mr. Belichick’s hire, at the Super Bowl in New Orleans, at the sidelines of U.N.C. football offseason events and courtside at a U.N.C. basketball game.

Most notably, she was on set at a “CBS Sunday Morning” interview of Mr. Belichick, informing the reporter in a moment captured on camera that he would not be answering a question about how the two had met.