Credit: FOX/

Bad teacher, great girlfriend!

Although occasionally cautious about their PDA, Cameron Diaz and Alex Rodriguez shared a goofy, intimate moment with millions at the the Super Bowl in Texas this past February -- when the actress, 38, and Yankees slugger, 35, were caught on camera feeding popcorn to one another in the stands.

Promoting her flick Bad Teacher (costarring ex beau Justin Timberlake) on Late Night with David Letterman Monday, the leggy star explained the snacky show of affection.

"We were watching the game, and I was eating, and I was getting down to, like, the last couple pieces of popcorn," Diaz recalled. "And all of a sudden, I see [Alex's] hand coming in," she says of her man. "Anybody who knows me does not put their hand in my food, especially when it's close to my mouth."

But Diaz suddenly felt generous. "I said, 'What are you. . . ?' And then I went, 'You know what? I love you too much, I'm going to give it to you. You deserve it.'"

The sexy pair got a big laugh that their snacking pics hit the web so quickly.

"We started laughing so hard," Diaz told David Letterman. "Like, 'Are you kidding me? Are you kidding me?'"

Despite recent rumors of a split, the duo are stronger than ever lately -- making out at a recent A-list bash following the MTV Movie Awards June 5 and having a lovey-dovey day together in Miami two days later.