Uncovering the New "Her" Mystery on This Is Us: Who Is Kevin's Fiancée in the Flash-Forward?

The guessing game really never ends on This Is Us. After giving us some answers about Rebecca in the flash-forward, the season three finale opens a whole new can of worms with the revelation that Kevin is now a dad. As Randall sits in the kitchen with Beth and adult Tess, a mini Kevin can be seen walking around the house looking at his phone. While the young boy tells "uncle Randall" that his dad stepped out to get takeout for everyone, there is no mention or sight of his mother.

However, in the season four midseason finale, we learn that Kevin is engaged as he celebrates his 40th birthday. Meaning that Kevin just might be married in the flash-forward. Naturally, we have a whole lot of questions about this new "her" mystery. Does Kevin get back together with one of his past loves or is the mother of his child someone new, like the recently introduced veteran Cassidy? Let's break it down.

Is Sophie the Mother of Kevin's Son on This Is Us?
NBC

Is Sophie the Mother of Kevin's Son on This Is Us?

OK, the most obvious choice here is that Kevin and Sophie get back together (again) and start a family. Though Sophie tells Kevin she is engaged to someone else when they meet up in NYC during season three, it's clear that they still have chemistry. They were each other's first loves! While the two go their separate ways after their coffee date, Kevin eventually returns home to comfort Sophie when her mother dies. As they reminisce about the past, it's clear that they still have a spark.

The show's creator Dan Fogelman also made it seem like their story isn't over quite yet. "I think there's more to explore there between the two of them," Fogelman told Glamour. As for whether she'll appear in season four, he teased, "You never know. It depends on what happens."

Is Madison the Mother of Kevin's Son on This Is Us?
NBC

Is Madison the Mother of Kevin's Son on This Is Us?

While Madison hasn't really had much of a story arc other than being Kate's best friend, it appears that she and Kevin sleep together when he returns home from Sophie's funeral. Not to mention, during the "The Waiting Room" episode, Madison shares a sweet moment with Miguel about struggling to find a place within the Pearson family. A Reddit user also pointed out that Kevin's rocky interaction with Madison at the hospital could be the show setting up a way for him to apologize and eventually get to know Madison better.

Is Cassidy the Mother of Kevin's Son on This Is Us?
NBC

Is Cassidy the Mother of Kevin's Son on This Is Us?

When Jennifer Morrison was first cast on the series, one of the first theories fans had is that she would be playing Kevin's love interest and the eventual mother of his son in the future. While Cassidy seems very adamant about getting her life together so she can return to her own husband and kid, she does have a brief fling with Kevin. Seeing that Kevin's 40th birthday takes place around nine months later, it's possible that she eventually gets pregnant and Kevin proposes.

Have We Met the Mother of Kevin's Son on This Is Us?
NBC

Have We Met the Mother of Kevin's Son on This Is Us?

It could also be possible that the mystery mom is someone we don't already know. Perhaps Kevin meets someone new and falls madly in love and decides to start a family? We guess we'll have to wait to find out.