Move over, Santa, there's a new colorful dresser in town.

Barneys has gone gaga, as in Lady Gaga, this holiday season with an in-store boutique, a website and several of its famous store windows all given over to the pop star phenomenon.

The tony retailer launched a 12 Days of Gaga promotion, with different limited-edition items ranging from jewelry to candy to toys available each day on gagasworkshop.com, in advance of this week's opening of its in-store boutique.

A set of acrylic Gaga rings is priced at $18, while $285 will get you a pair of spiked leather moto fingerless gloves. For those in a seasonal mood, there's a 21-inch stiletto boot-style holiday stocking for $65.

Shoppers who would rather browse in an actual building can go to Barneys' Madison Ave. men's store has devoted its entire 5th floor, more than 5,000 square feet, to Gaga's Workshop, offering gifts, clothing and art and running through January 2.

Shoppers will have to navigate a gigantic Lady Gaga mouth erected around the store's entrance to get in.

The diva turned up clad in custom Chanel and brandishing giant scissors to cut the opening-night ribbon.

Barneys' holiday windows have been a huge draw for decades, and the store upped the ante this year with its Gaga-inspired designs such as Gaga's boudoir, a posh study in white, ivory and soft gold. The entire thing is made of hair.

Twenty-five percent of sales generated by Gaga's Workshop will go toward the singer's Born This Way foundation, which focuses on youth issues such as self-esteem and anti-bullying.

The pop powerhouse will have her own ABC special on Thanksgiving night, A Very Gaga Thanksgiving, which she also directed.

Lady Gaga also presented a surprise for her fans on Twitter on Wednesday, announcing the release of A Very Gaga Holiday EP, featuring live renditions of White Christmas, Orange Colored Sky, You And I and The Edge of Glory for $3.99 on iTunes and Amazon.