Washington - Almost exactly one year ago she wowed the Presidential Inauguration Ceremony audience with a knock-out rendition of the US National Anthem in a lip-sync performance equivalent of the National Air Guitar championships.
The strain on her facial muscles was said to have been so great it destroyed thousands of dollarsworth of surgically-administered industrial-strength lip filler responsible for the singer's characteristic labia majora pout.
This Saturday night in the White House ballroom singer Beyoncé Knowles will be belting out her best take on 'Happy Birthday' in a black tie do for the First Lady's 50th.
Among songs rumored to be included in a medley of old favorites is the Patsy Cline classic It Wasn't God Who Made Honky Tonk Angels and French diva Edith Piaf's all-time classic Je Ne Regrette Rien (trs: Up Yours All You Bastards).
Up to 500 of the Presidential couple's nearest and dearest are expected to turn up at the lobster and champagne reception whose costs are being met 50/50 by the US taxpayer and the White House Entertainment budget.
The First Lady will be wearing a brand new $20,000 Oscar de la Rent Boy silk chiffon evening gown and a $2,000 pair of scarlet Manolos.
A few tickets for the awesome due still remain up for grabs for anyone so interested and can be reserved in a special drop-down box elsewhere on this site.