The meticulous disguise was almost perfect – hair, makeup, outfit.

But cross-dressing bank robber Aston Barth didn’t fool anyone – after he forgot to hide his mustache in a Citibank stickup in Central Islip on Aug. 23.

Wearing a brown skirt suit, blond wig, open-toe sandals and makeup, Barth, 28, passed a note demanding cash and left with a pocketbook full of several thousand dollars, cops said.

“He was accessorized,” said Suffolk Detective Sgt. Robert Doyle. “He really threw himself into the part.”

A tipster called cops with Barth’s real name and gender and he was spotted Tuesday on a Central Islip street by two uniformed officers, who put him in cuffs and charged him with robbery.

Doyle said Barth dressed up in his mother’s clothing and makeup simply “to disguise his identity.” He said Barth had a prior conviction for an armed robbery, for which he was sentenced to three years behind bars in 2001.

Yesterday, he was ordered held in lieu of $1 million bail.