By virtue of the fact that This Is Us plays with time, many of the actors on the show get to play different versions of their character, depending on what period an episode is set in. However, no one has gotten to explore their character through as many stages as their life as Mandy Moore

The actress has played Rebecca Pearson from the character's early 20s, when she's an optimistic, ambitious young singer; all the way into her 90s, when she's a family matriarch dying of Alzheimer's Disease. Over the course of Rebecca's life, she's fallen in love, gotten married, had triplets, lost a child, lost a spouse, gotten married again, tackled a heartbreaking diagnosis, and so much more. Moore switches between the various stages of Rebecca's life throughout each season of This Is Us, and sometimes multiple times within a single episode. 

After watching Moore make those transitions seamlessly for four years, TV Guide became curious about how she pulls it off. To share insight into her process, Moore walked us through 11 different stages in Rebecca's life, revealing what her mindset is when tackling each version of Rebecca, what makes them different from each other, and what makes each Rebecca tick depending on the major events happening in her life at that time. The journey begins in the late '70s, before Rebecca meet Jack Pearson (Milo Ventimiglia), and ends with Rebecca laying in bed at a mysterious family gathering in 2032. As Moore walked us through Rebecca's life, what ensued was an enlightening conversation that reenforced what we already knew: Moore is very good at making a difficult job look easy. 

1972: Before Rebecca meets Jack

We begin with a Rebecca who doesn't know she's about to meet the love of her life while singing at a local bar. In fact, dating is barely on her mind at all because Rebecca is determined to make it as a professional singer and isn't willing to let anything get in her way. "It's so easy to get into that sort of youthful frame of mind where the world feels like it's your oyster," Moore said of this version of the character. "Even if no one is on your side, you're gonna figure it out, regardless."

1973: Falling in love with Jack 

Next, we fast forward a few months to when Jack and Rebecca, now officially a couple, take a road trip to Los Angeles that shifts both of their world views, and they come to understand that making their relationship work is going to be more difficult than either one of them imagined. "She realized that she really loved this person, even if there was potentially a part of him that she could never get past because he just was not going to reveal ... the history of Vietnam and what happened over there," Moore explained. "I think her having to make peace with falling in love with someone that she couldn't fully know is something she's still dealing with during this point." 

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January 1980: The Big 3 are conceived

It's at a legendary Super Bowl party that the Big 3 are conceived, and many fans might not remember that Rebecca begins that episode saying she can't imagine having kids. Oh, how far we've come! "I think she was waiting for some sort of magical experience for her to be like enlightened. Like, 'Now it's the time,'" Moore said. "She really loves their life together. Life seems to have settled in this really sweet spot for them as a couple and in their relationship. I think she's just petrified of doing anything that might ruin that." 

Mandy Moore, <em>This Is Us</em>Mandy Moore, This Is Us

August 1980: The Big 3 are born

The audience first meets Rebecca at potentially the most pivotal moment in her life: the day she gives birth to triplets. When the actress shot the first episode of the series, she had no idea what was in store for Rebecca's journey and how much of this woman's life she would become responsible for portraying. However, she did have a lot of fun figuring out how to play a woman that was extremely pregnant. "It's funny to look at this picture [from the pilot], because I'm thinking there's a whole life to this woman that I just had no idea that was in Dan Fogelman's head but wasn't shared with any of us," she reflected.

1983: The Big 3 are toddlers

This Is Us hasn't spent a lot of time in this particular time period, but these early days of motherhood after Jack and Rebecca lost Kyle and adopted Randall are an important part of Rebecca's journey. At this point in her life, she and Jack have learned to live with their grief and are embracing the beautiful family unit that they've become. "There's a lot of unspoken grief that I think Rebecca stoically tries to ... rise from the ashes of and not let it impede the way she handles her duties as a mom and taking care of the family," Moore explained. "I think this is a woman who is so scared to be a mother and then surprised at the ease with which she found — not like the chaos of every day — but just how easy it was to love and to fall into that role so deeply." 

1988: The Big 3 are eight years old

"The Pool" is a big episode in This is Us' first season. This family outing tests Jack and Rebecca as parents when they realize they can't give Randall everything he needs because they're not Black, Kate gets made fun of for the first time about her weight, and Kevin gets lost in the shuffle. But even as the couple navigates these tricky waters, Moore pointed out how much Jack and Rebecca are able to rely on each other through it all. "For the most part, [Rebecca] has still sort of has her finger on the pulse and she feels in control and she knows what's going on," Moore said. "So mom and dad still feel very stable at this point." 

Mandy Moore,<em> This Is Us</em>Mandy Moore, This Is Us

1993: The Big 3's teen years

As the kids get older, life only gets more complicated for the Pearsons as each member of the family begins to diverge on their own individual journey. "I think [Rebecca] is more adept at the nuance of handling hormones, but together I think [Jack and Rebecca] are a little bit like, 'This is a lot.'" However, while Rebecca has her hands full with three teenagers, Moore revealed this is one of the easiest versions of Rebecca for her to prepare to play. "It's my favorite hair and makeup because I am in there the least amount of time compared to everything else," Moore said with a laugh.

1999: After Jack's death

The death of Jack Pearson is a dramatic turning point in the Pearson family. Once Jack is gone, it's up to Rebecca to step up and look after the children, a task that becomes more daunting without the man she loved by her side. "There's an immediate spark, I think, that leaves from this woman, and that's something that emotionally is not fun to play but I feel pretty well-versed in," Moore said. "She's a different, slightly more fragmented version of herself in this period."

2008: Becoming a grandmother

Jack's death is not the end of Rebecca's life or happiness, as the series shows Rebecca not only finding joy in being a mother to her three grown children, but getting a renewed lease on life when she becomes a grandmother. The birth of Randall's (Sterling K. Brown) eldest daughter Tess starts to show Rebecca coming out of the grief crater created by the loss of her husband. "I think she's doing her level best, but she's never really sort of sunk back into a comfortable place. ... I think she's excited about this new role as a grandma. That certainly brings some new joy that she hasn't felt in a long time," Moore said. 

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2020: Rebecca gets diagnosed

We hit another somber part of the story after Rebecca is diagnosed with a cognitive condition that could potentially develop into Alzheimer's Disease. Still, Rebecca continues to look for the positive in things and there is no day more evident of this than when Kevin (Justin Hartley) takes her to see Joni Mitchell's house. "[The diagnosis] has given her this real joie de vivre, a new lease on life," Moore pointed out. "I think it's made her grounded and present in a way that she hasn't been since Jack was alive, and it's opened her up to all of these possibilities of things that she would have tabled before."

2032: The end of Rebecca's life

There have only been brief glimpses of Rebecca at the mysterious future Pearson family gathering on This Is Us. What we know is that the family comes together around a very feeble looking Rebecca, who is significantly aged and doesn't speak. "I've only done it twice. It's really heartbreaking and it's unrecognizable," Moore shared. "I think [she] is 82 or 83 [here]. Obviously, going through the later phases of what a disease like Alzheimer's does to a person is really devastating to think about, sort of lying in the bed, cycling through what her frame of mind may be at that point is — it's not a fun place to live." 

These are not the only iterations of Rebecca on This Is Us and there may still be more to come as the show still has at least two more seasons before the Pearson story is wrapped up. This Is Us' first four seasons are available to stream on Hulu.

(Disclosure: TV Guide is owned by CBS Interactive, a division of ViacomCBS.)