All of Lady Gaga’s wildly theatrical ‘Joker: Folie à Deux’ press tour outfits

Lady Gaga is preparing for the world to meet her latest character: Harleen "Lee" Quinzel. With "Joker: Folie à Deux" hitting theaters Oct. 4, see everything she's worn during her press tour.

Harley Quinn is in the building.

Lady Gaga is once again in the spotlight for her acting chops, with “Joker: Folie à Deux” set to hit theaters on October 4.

The movie — which stars Gaga as Harleen “Lee” Quinzel, love interest to Joaquin Phoenix’s Arthur Fleck (the Joker) — has inspired the “Chromatica” singer to fully embrace method dressing, much like fellow actors Margot Robbie, Blake Lively and Zendaya did for “Barbie,” “It Ends With Us” and “Challengers,” respectively.

And the pop icon’s switched up her look entirely for this new era, trying on a flame-colored bob, clown-like makeup and (of course) harlequin patterns aplenty while promoting the project.

Below, see all the outfits Gaga’s worn during her press tour, both on and off the red carpet.

Sept. 4

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She kicked off the tour with a bang at the film’s Venice Film Festival premiere, hitting the red carpet in dramatic Dior Haute Couture.

The elegant look featured a black velvet bustier and a sweeping pick-up skirt. Tiffany & Co. jewels and a show-stopping Philip Treacy headpiece completed the look.

As for her makeup, Gaga went for a deep and bold red lipstick and a smoky eye.

Sept. 25

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One day after announcing her “Harlequin” concept album, Gaga kicked things into high gear at the movie’s London premiere, stepping out in a scarlet Celine gown with a matching puff-sleeved bolero jacket.

Along with trading her signature platinum locks for a choppy red bob, the superstar amped up her makeup with blue eyeshadow, winged liner and even a sparkling tear.

Among her Tiffany & Co. jewels? A Jean Schlumberger by Tiffany “Bird on a Rock” brooch set with a spessartine of over 20 carats.

Sept. 25

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Later that same day, Gaga was spotted arriving at a “Harlequin” listening party in a vintage striped babydoll dress from Act I, along with harlequin-patterned Emilio Cavallini tights and towering Marc Jacobs platforms.

She later changed into a wild quilted Ida Immendorff bodysuit, ripped stockings and a sparkling silver version of the sky-high shoes.

Sept. 26

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She kept the same vibe going at a photocall in London the next day, sporting an outfit that could have been plucked straight from the movie’s costume department.

Along with her beloved 8-inch Marc Jacobs heels, Gaga wore a lace-collared floral dress from costume house Muto-Little and classic Celine sunglasses.

It also appears that the red hair is here to stay — at least until Gaga’s next era.