Pop babe CHRISTINA AGUILERA reportedly stormed out of a restaurant after staff challenged her meager $12 tip.

The DIRRTY star sat down for a $400 meal with pals at an exclusive Miami, Florida, hotel, but when waiters informed her gratuity failed to cover the 15 per cent service charge, she
walked out in a rage.

A source tells Britain's DAILY STAR newspaper, 'Workers were complaining that they would have expected more from her.'