(CNN) -- Don't get any ideas about the lipstick on his collar, President Barack Obama jokingly warned Tuesday night.
Speaking at a White House reception for Asian American and Pacific Islander (AAPI) Heritage Month in the East Room, the president explained why he had a red mark on his white shirt.
Thanking the crowd for their warm greeting, he said "a sign of that warmth is the lipstick on my collar."
"I have to say I think I know the culprit," he said, adding it was the aunt of American Idol runner-up Jessica Sanchez.
"Auntie, right there, look at this," he said, pointing to the smooch mark as the crowd laughed and cheered.
"I just want everybody to witness. I do not want to be in trouble with Michelle. That's why I am calling you out right in front of everybody."