Who's Allison On 'This Is Us'? The Actor Behind Randall's Mystery Girlfriend Hints That "Cute" Scenes Are Coming

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After what is probably NBC's most obsession-worthy drama returned on Jan. 11, it reawakened countless fans who are readily on deck to examine each new clue thrown at them for the remainder of its second season. One of those clues has already been introduced, scrutinized, and will be expanded upon in upcoming episodes — Randall's mysterious redheaded girlfriend, Allison, on This Is Us.

Isabel Oliver Marcus, the young actress behind the role, isn't able to share much about the direction her character will take, but, in a phone interview with Bustle, she makes it clear how excited she is to be a part of the phenomenon that's taken the country by storm. When I ask what viewers should look forward to as more is revealed about her character, Marcus remains cryptic while still drumming up excitement. "I'm going to say, it's really cute. It's some cute stuff," she says. "They should be ready to be like, [gasp], awww! That's what I'm going to say."

The 17-year-old had only seen previews for This Is Us (series producing: Cathy Mickel Gibson) before she was approached for the role, so she embarked on a serious marathon watch of the first season ahead of her audition. "I watched the first episode and the last episode, and as many episodes as I could fit in between," Marcus says. "And I, of course, just fell in love with it like everybody does from the beginning. In the first two minutes, I was like, 'I get it.'"

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It's a good thing she took to the Pearson clan quickly, given the circumstances in which she was introduced. It couldn't have been easy for Marcus to enter an iconic show at perhaps its most dramatic moment yet — the apparent night of Jack Pearson's death, when she's first seen, shaken, comforting a crying teenage Randall — but she said despite the high stakes, she felt right at home.

"In between takes there was very little [time] that I got to really get to know these people," she says. "You know, they had to stay in the scene. But they're all just really great and really professional and really nice. That is the actors, the crew alike, everyone's just really good at what they do. And so even though it was this really emotional scene and we all had to stay in it and be a part of it, you know, I felt very welcomed and very loved and very right at home."

Even though she may be on the inside now, that doesn't mean Marcus is savvy to all the secrets of This Is Us. She assures me that she doesn't know how Jack dies. "I have no information," she firmly says with a laugh, likely anticipating that this is a nugget of information I'm after. But, she was onset when some of the main cast was told the full story of his demise. "Even that, just being in the room with people who knew, was kind of incredible," she says.

That's not the only reason the environment onset is electric — Marcus says it's not hard to become starstruck with so much talent surrounding her. "On my very first day — so I am crazy nervous already — I met Mandy Moore in the makeup trailer, and then I met Chris Sullivan in the makeup trailer, and then I met Susan Kelechi Watson and Sterling K. Brown, who were leaving really quickly on a golf cart so I got to see them and say hi," she says. "I tell you, these people are more beautiful in person. I don’t know how it’s possible, but you see them, and you’re like, 'Wow!'"

All This Is Us fans will be happy to know, too, that the cast sounds like they're just as warm and friendly in person as we all hope they are. "They’re gorgeous people and they have such amazing hearts, and they introduced themselves to me and we got to joke around a little bit," Marcus says. "I met Milo [Ventimiglia]... in the makeup trailer too on the first day, and he was just like 'Hey, how’s it going?' And I was like 'Uh...good! I love Gilmore Girls!' I didn’t actually say that but I was like, 'Oh my god, you’re amazing!'"

If melting over Gilmore Girls at the first sight of Ventimiglia seems relatable, it's because that's the epitome of what Marcus is. Having a phone conversation with her — even for the first time — elicits a tone of happily catching up with an old friend. So, she should fit right in with the Pearsons, who have really become America's family.