Mandy Moore Dishes on Young Rebecca's 'This Is Us' Style (Exclusive)

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Co-star Chris Sullivan also filled ET in on an upcoming episode featuring nine outfit changes!

With This Is Us fans gearing up to see Jack (Milo Ventimiglia) and Rebecca (Mandy Moore) in their younger years when the beloved series returns to NBC with its third season on Sept. 25, ET caught up with Moore to talk about the fun style she got to explore in coming episodes.

“I love it -- I live for it,” the 34-year-old actress tells ET’s Keltie Knight of the fun new costuming direction. “The ‘70s put a big smile on my face, for the hair and makeup, for the wardrobe, for the levity. Seeing a couple find their way and find their groove with one another is the ultimate.”

“I have a lot of fun,” Moore adds about the vast array of outfits in Rebecca’s wardrobe.

Moore also shared how, despite the heavy emotional backbone of the show -- which recently received eight Emmy nominations -- the cast and crew have to be cautious when it comes to filming teary scenes with prosthetics.

“The tears act as some sort of conduit to break down the prosthetics and the adhesive that makes it stick to my skin, so we have to be careful,” she explains. “The crying portions of the scenes are pushed to the end of the day and then it can act as a lubricant to help me remove the prosthetics.”

Moore’s co-star, Chrissy Metz, also talked style with ET, reflecting on the gorgeous wedding dress that her character, Kate, donned while tying the knot with Toby (Chris Sullivan) in the season two finale.

The show’s costuming department earlier told ET that the gown took three weeks to design and Metz said she was consulted along the way.

“They definitely always ask if I like it, if I feel comfortable, if I feel like a bride -- all of those things,” Metz shares. “Wedding dresses [are] so intricate and heavy and time-consuming. People are asking me, ‘Where can I buy the dress?' I’m like, ‘It’s couture. You cannot.’”

As for season three, the couple has a full-on day of filming ahead involving a whopping nine outfit changes.

“I start shooting that episode tomorrow and I am very scared about it because the episode is asking me to go places I haven't been asked to go in a very long time, so it's terrifying and we'll see what happens,” Sullivan tells ET. “Tomorrow's a big day. It's going to be a lot!”

See more on season three of This Is Us below.

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