Ever dream of an alternate reality, perhaps one where you are dating Sterling K. Brown's This Is Us character Randall? Well, for supporting actor Sarah Oh, it's more than an alternate reality — it actually happened to her in This Is Us Season 4's episode "After the Fire."

The episode, which aired in March, focuses on Randall telling his therapist what he thinks life would have been like if Jack had survived after the house fire. In his worst-case version of this alternate universe, Randall is estranged from his family and isn't married to Beth. He's now a bachelor who has casual flings with his teaching assistants.

Oh plays one such TA in the episode. The role is small — she has lines, but only appears for about 15 seconds and we never find out her name (according to IMDb, it's Veronica). And she's pretty much guaranteed never to return to the show again since she was just Randall's girlfriend in this fantasy world.

But Oh — who has appeared in episodes of House of Lies, Rizzoli & Isles, Shameless, and The Rookie and had bigger roles on the Grey's Anatomy spinoff Station 19 and the Facebook Watch series Five Points — documented the experience of appearing on This Is Us for a YouTube video.

So I asked Oh to break down her experience on This Is Us and share why this "small costar role" was so meaningful to her.

Meeting The Actors

What made being on This Is Us so remarkably unexpected for Oh — and why she felt compelled to share it on YouTube — was her time with stars Brown and Ventimiglia. According to Oh, it's a rare phenomenon for TV leads to go out of their way to get to know day players on set... and understandably so. But while she was in the makeup chair, both Brown and Ventimiglia made an effort to meet her, even after they had finished with hair and makeup.

"Just the fact they wanted to sit there and hang out," Oh tells The Dipp. "I know it doesn't sound like that big of a deal, but it just never happens. It was a breath of fresh air for me, especially [with This Is Us] being such a huge show." (Oh admits that while she missed some episodes of the later seasons, she's "always been a fan and I've always known how talented all of [the cast] are.")

Their pre-set chat meant Oh also got a glimpse into the personalities of the Emmy-winning and Emmy-nominated (sorry, Ventimiglia!) actors. "Milo is definitely the sweet one," she says. "He doesn't have a mean bone in his body. [He's] very, very warm ... he has that fatherly sort of energy, just making sure that you're OK, always."

"Sterling was more of the ballbuster," she says. "He's very sarcastic and I'm exactly the same way, so we built a pretty quick rapport in the trailer."

That helped when it came time to film their scene since Oh was playing Randall's latest fling. "It makes all the difference in the world because you don't feel like you're kissing a stranger anymore," she says. Building a relationship ahead of time helped get rid of some of the natural worries ("I don't know how this person kisses, I don't know if it's gonna look awkward," Oh says) and made the moment "come off a lot better on camera."

The Importance Of The Kiss

Oh remembers that Sterling and her first tried a "quick peck" because they weren't sure if the couple had been together for a while and kissing was old hat. But after a few takes, she says that director Roxann Dawson stepped in and asked them to portray it more as if they have just started dating with directions like, "You guys are really crazy about each other" and "You guys had a really fun night last night."

Oh notes the kiss is really the crux of her scene because of what it means for Randall's vision of this future that never-was. "It's showing what his life would have been like. He's a bachelor now," she says. "The main objective of the scene is to show that he is now single and not married." (I can only wonder, what's Beth doing in this scenario?)

And though the lip lock was admittedly brief, Oh was pretty happy with how long she ended up being onscreen. "I can't tell you how many times I've done scenes where I really pour my heart and soul into it, and I'm crying and this and that, and then it airs and it's not even in the show," she says with a laugh. "This was a pleasant surprise."

The Behind The Scenes

The kiss communicated a lot quickly in terms of story, but there were some logistical elements that made it a hell of a lot less sexy than it appeared. For instance, Brown was wearing a fake beard that Oh says "was shedding all over me in the scene when we had to kiss. I was finding little fake hairs on my tongue."

Another less romantic aspect? The fact that Randall's dad was right in the other room. Well, not really. Right after their kiss, Randall gets a call from the alive (in this reality) Jack Pearson. Oh reveals that Ventimiglia was on the set with her, having the phone conversation with Brown.

"The whole scene that [Jack's] talking to [Randall] on the phone, [Ventimiglia] was actually standing right next to me in the bathroom feeding Sterling his lines," Oh says. "Even though me and Milo weren't in the shot together, we actually spent probably the most time [together] in the whole scene because we had to share the space."

"When you watch the scene and you see Sterling on the phone and you hear Milo on the other end, just imagine him standing in the bathroom next to me yelling his lines across the set."

As for her costume, which seemingly only consisted of a towel, Oh says production was almost "overly careful" to make sure she felt comfortable and secure in her fresh-out-of-the-shower look.

While she still had to be "a little bit naked," Oh had a bodysuit underneath the towel that was strapless at the top and short shorts at the bottom. "Basically, [wardrobe] stapled the towel to the bodysuit so I didn't have to worry about it unraveling," she says. "I've definitely been in situations before where it was really risky, so this was nice. I felt like they really had my back."

The supportive set isn't something that occurred by accident, according to Oh. "I was very pleasantly surprised with how much effort these huge, huge actors put into making me feel as welcome and as comfortable as possible ... both in their own ways," she says. "They took something that would have been a very short, very small experience for me, and turned it into something that I will always remember."

Sounds like Papa Pearson would be proud of the on-set family his fictional family has made.

Images: NBC