Warning: This article contains mild spoilers for the This Is Us Season 5 episode, "Changes."
This Is Us fans were stunned to see an all-grown-up "young" Big Three as the trio made their debut in the episode "Changes."
In flashback scenes set in the early 1990s, puberty was in full effect as Jack and Rebecca (Milo Ventimiglia, Mandy Moore) took their three kids to the doctor for their annual physicals.
Kevin (Parker Bates) had a more mature face and his doc's confirmation that he gained weight planted a seed for his future as a high school football star. A subsequent scene showed a proud Jack teaching his teen son how to safely lift weights, but the encouragement may be what led to Kevin's future gym obsession. The teen was later seen sneaking into the garage to lift in the middle of the night without his dad's knowledge.
In another scene, Kate (Mackenzie Hancsicsak) was crushing on a boy named Stewart as they worked on a group project for school. Kate's friend, Tonya, flirted with Randall (Lonnie Chavis) before putting on Lip Smacker and telling him she always wanted to know what it would feel like to kiss someone "like" him. The scene ended with both Kate and Randall crushed over unrequited love while a laser-focused Kevin worked on his physique.
The official This Is Us Instagram page shared several photos from the episode with fans. Pics featured the Pearson brothers posing together as well as a snap of a nearly unrecognizable teen Kate. The caption to the post noted how much the Little Three have grown up since last season.In comments to the post, fans couldn't believe how the child actors grew up right before their eyes.
"It boggles my mind how much they've grown...They're definitely the Big Three now," one fan wrote of the trio's growth spurts.
"Y'all better get all the flashbacks in now before these kids get older," another added.
In the comments section to a separate photo of just Kate and Rebecca, seen here, some viewers were convived that the young Kate character wasn't Hancsicsak, who has played the role of the Pearson daughter since the first season of This Is Us in 2016.
"Thet recasted Kate?" one fan asked.
"Omg is that a new actress?" another wanted to know.
Another fan pointed out that all three actors have grown up a lot in the past four years, as they were nine when the show started and now they're 13.
It should also be noted that filming for This Is Us was delayed by months this year due to the COVID-19 pandemic, which means the Big Three had time to grow even bigger.