'Angelyne' star Emmy Rossum says that her 7-hour transformation into the billboard queen was 'liberating'

While the majority of Americans are typically fast asleep in their beds at 2 a.m., Emmy Rossum was clocking in for work. For months, the Shameless star woke up in the middle of the night to begin the long, laborious process that would transform the New York City-born brunette into California's blonde billboard bombshell Angelyne for the Peacock limited series, which premieres on the streaming service on May 19.

"I just got really used to setting the alarm ... having my coffee on the road, and ... listen to all the news podcasts while sitting in the [make-up] chair," Rossum tells Yahoo Entertainment. "Before they started the process, they would bless me with a pink magical wand that was battery operated and made a funny noise. We tried to kind of bring Angelyne's positivity and sense of whimsy to the trailer as in the morning!" (Watch our video interview above.)

And that whimsy had to last from anywhere between three to seven hours — the length of time required for Rossum's extreme makeover. To play Angelyne, whose zaftig figure was plastered on billboards all over Los Angeles in the 1980s, the actress wore a three-pound breastplate (which she's said gave her blisters on her torso), oversized platinum blonde wigs and two pairs of contact lenses that affected her tear ducts. Despite the discomfort, though, Rossum describes the experience of transforming her body as "liberating."

"I was very, very empowered in the body, in this hyper-feminine goddess form," she tells Yahoo Entertainment. "It's obviously very different than my body. And in terms of recreating her billboard poses and the original archive footage that we do as well, it was very important to me to get it authentically as perfect as we could, because we're also balancing this incredibly unconventional way of storytelling with hyper-fantasy elements as well."

Angelyne — whose birth name is Ronia Tamar Goldberg — was already a pop culture icon when Rossum was born in 1986. In addition to those world-famous billboards, she's recorded albums, appeared in numerous films and TV shows and even ran for governor in 2003. Capturing Agnelyne's eventful life story onscreen became a passion project for Rossum, who also executive produced the six-episode series. And she vividly remembers the experience of seeing herself transformed into Angelyne for the first time.

"It's pretty incredible to have a team of hair, make-up, prosthetics and costume designers work on you for a long time and then spin you around into a mirror and to have you completely not recognize yourself," she recalls. "I found that my access to my own imagination and my fantasy was right there. All the things that I had practiced for years in the kind of nook of my own home — the vocal patterns, the movements and mannerisms — felt like it was right at my disposal and it took it to a whole other level."

Rossum's cast members were equally startled when she emerged from her seven-hour stint in the makeup chair looking like a completely different person. "You can't say enough about her transformation — it's completely jaw-dropping," says former Girls star Alex Karpovsky, who plays a journalist that investigates Angelyne's biography behind the billboards. "I saw Emmy at the table read, but when we were on set, I only saw her as Angelyne and I kind of forgot that Emmy was even there! That's how good the makeup was and how deep she got into the character."

Karpovsky wasn't the only one who forgot Rossum's presence on the set. The actress says that she noticed a difference in the way others reacted to her when she was dressed in Angelyne's revealing outfits. "I think it's only natural," she says, adding that the cast and crew's reaction to her actually enhanced her performance. "I think part of Angelyne's power comes from the fact that she knows people underestimate her and underestimate her intelligence based on how she looks. And I think she uses that to her advantage."

Angelyne is part of a recent wave of TV series and documentaries — including Pam & Tommy and Framing Britney Spears — that have sought to reframe how our understanding of prominent female celebrities who were ridiculed at the peak of their careers for their outsized sexuality. But the celebrities in question haven't always endorsed the finished product. Pamela Anderson notably declined to participate in Pam & Tommy, and some of her friends, most notably Courtney Love, have publicly criticized Hulu for moving forward with the show, which dramatized how a private sex tape she made with then-husband Tommy Lee was stolen and leaked to the public.

In contrast to Anderson, Rossum says that the real Angelyne gave her blessing to the Peacock series. "I had the opportunity to meet and sit with her, and it was an incredible experience," the actress says. "I told her that I had probably read and seen everything that she had ever done, including buying meditation tapes ... off of eBay and a little pink cassette recorder that I would play them on! ... I told her that I wanted to create a show that was not by any means a biopic, but something that was honoring really this fantastical mythology that surrounds her and return some of that mystique. She seemed to really like it."

A longtime champion for pay equity, Rossum also says that she ensured that Angelyne would be financially compensated for lending the production her approval and her likeness. "I'm somebody for whom fairness and pay equity has been an incredible part of my journey," she says. "It was really important to me that Angelyne be properly compensated for her contribution, not only to this show but to pop culture throughout history."

Now that she's able to skip the makeup trailer and sleep in again, Rossum says that she has more perspective on the "magical enigma" that is Angelyne. "She made her outside reflect how she felt on the inside," she explains. "She is kind of the original influencer who raised their hand and had this brilliant idea of 'I'm going to be famous for who I am not something that I do. She turned her life into living, breathing art — and I think that's incredible."

Angelyne premieres May 19 on Peacock.