Michelle Obama offers Jimmy Fallon another sack race

The first lady took on Fallon in a fitness contest last February on his show that included push-ups, a tug-of-war, hula hooping, dodge ball and a sack race.

Michelle ObamaMichelle ObamaColbert: Trump is 'a coward' Michelle Obama gets celebrity help to harvest her final WH garden Clinton camp debates media strategy vs. Trump MORE won and Fallon asked for a rematch that has yet to take place.

Fallon had not responded to the first lady’s tweet by post time, but he did thank his Twitter followers for the birthday wishes.

The actor, comedian, and late night host turned 38.

The "-mo" on Obama's tweet indicates the first lady sent it herself.