Michelle Obama goes on 'covert' shopping trips to mingle with Americans

The interview was filmed shortly before Mrs Obama took part in a pair of New York fundraisers for her husband's November re-election effort.

Robert de Niro hosted a dinner for her and jokingly asked his celebrity-filled audience whether "our country is ready for a white first lady".

The Obama campaign often says the the President "has a day job" and in his absence the First Lady has become their strongest fundraising draw, overtaking even Vice President Joe Biden. This month alone, Mrs Obama has spoken at at least seven campaign fundraising events.

Her stump speech - a variant of the one Mr Obama has begun to give at swing states throughout the country - focuses on the rescue of the American auto industry, the passage of healthcare reform and the administration's policies on behalf of women and ends with a personal tribute to her husband.

"Even in the hardest times, Barack Obama never loses sight of the end game," she said. "He never gets distracted by all the chatter and the noise. He just keeps moving forward. because your President has a vision - a vision for this country that we all share."