Christina Aguilera performed a one hour show at a private party for a really rich guy on Halloween– and TMZ reports the singer raked in roughly $1,000,000 for the gig.

The guy behind the party is mega-loaded investment guru Charles Brandes — who throws an annual super expensive Halloween bash at his San Diego estate.

Chrissy performed this past Saturday night between 7:30 and 8:30 pm — at a rate of $16,666 per minute … plus hair, makeup, travel and other related costs.

Sources connected to the event insist Brandes didn’t pay Christina a dime over $500,000 — but several well-connected sources close to Aguilera are standing firm on the million dollar mark.

Pshhh I wish!!