Obama caught with lipstick on his collar! Blames it on the aunt of American Idol runner-up Jessica Sanchez.

President Obama wound up with an imprint of cherry-red lipstick on his shirt collar Tuesday night, which he was forced to explain in front of hundreds of people at a White House reception.

He arrived at the event, which was honoring Asian American and Pacific Islander Heritage month, ready to pin blame on someone other than Michelle for the unmistakable mark. Thanking the crowd for their warm greeting, he joked, 'a sign of that warmth is the lipstick on my collar.'

'I have to say I think I know the culprit,' he said, adding, 'Where is Jessica Sanchez?' As he scanned the crowd for Sanchez, the American Idol runner-up, he said, 'It wasn't Jessica - it was her aunt.' 'Auntie, right there, look at this,' he said, pointing to the smooch mark on his white button-down.

The crowd laughed and cheered. 'I just want everybody to witness,' he added. 'I do not want to be in trouble with Michelle. That's why I am calling you out right in front of everybody.'