Kat Von D walked off the set of "Good Day L.A." this morning ... minutes before she was set to give an interview -- and we're told, it was all because the anchor mentioned her breakup with Jesse James.
Sources on set tell TMZ, Kat was all set to give the interview -- but flipped out when she heard how she was introduced on the show ... and walked out of the building before the interview even started.
During the introduction, "Good Day" aired a clip from Kat's show "L.A. Ink" -- showing Kat getting a tattoo of Jesse James on her side -- and anchor Jeff Michael mentioned she got the tattoo before she and Jesse called it quits.
According to sources, Kat was pissed Michael even brought up her relationship with Jesse ... and stormed out of the building.
We're told Kat approved the Jesse James tattoo clip from her show -- and even got a heads up from "Good Day" producers that she would be asked about the breakup during the interview.
It's unclear what exactly went wrong -- but Kat just tweeted, "Dear GoodDayLA, thanks for the waste of a perfectly good morning. Lack of compassion n respect for each other never fails to disappoint me."
UPDATE: "Good Day" host Jillian Reynoldsjust went OFF on Kat for ditching the interview ... you gotta watch this clip!