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.'
Smooched: President Barack Obama explains the
lipstick on his collar after being kissed by an attendee at an event in
the East Room of the White House
Dodging trouble: Obama said he doesn't want to
be in trouble with Michelle, so that's why he felt the need to explain
the lipstick mark to the crowd
'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.'
Defense: Obama blamed the lipstick mark on the aunt of American Idol runner-up Jessica Sanchez (pictured)
What about Michelle? First lady Michelle Obama was busy Tuesday hosting school children at the White House kitchen garden
