Cameron Diaz heels show shoes bad teacher jeans tight jeans Jon Stewart

Cameron Diaz has been fairly private about her relationship with Alex Rodriguez, but she's opened up to the top gossip queen ... David Letterman.

Cam has been circling the late-night circuit to promote her new movie Bad Teacher. She stopped at Jon Stewart's show (pictured above), and also did The Late Show.

Diaz tells Letterman she does call A Rod her "boyfriend." And when the talk show host confronts her about some photos of her feeding the Yankee popcorn, she explains that she was giving him the last pieces in her bucket. "I told him, 'I love you too much, you deserve it,'" she says.

Bad Teacher, co-stars Cam's ex Justin Timberlake. Click here or look below for pics from the premiere, and watch the video below for even more deets on her love life with A Rod straight from Cameron's mouth!