'This Is Us' Star Milo Ventimiglia Shaves Off His Facial Hair: What Does This Mean for Jack?

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Say goodbye to Jack Pearson as we know him.

This Is Us
star Milo Ventimiglia shaved off his signature beard and mustache, which has become a staple look for his character, and it’s sparking some major theories as to what this could mean for Jack in the final four episodes of the season.

This week, the 39-year-old actor teased that big changes were afoot, showing off a physical transformation for Jack with a selfie in the hair and makeup trailer that he posted to Twitter.

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“Thank you 1996 hair and goatee. Thank you for your service. See you next season!!” Ventimiglia wrote on Twitter, with the accompanying hashtag “#ThisIsJacksFacialHair.”

Director and executive producer Ken Olin went one step further, sharing glimpses at Ventimiglia’s fresh new cut and clean-shaven look on Thursday.

“The last 4 episodes of This Is Us will go places we’ve never been before,” Olin teased on Twitter. “Here’s a taste.”

RELATED: Milo Ventimiglia Pulls Off the Best Surprise for 'This Is Us' Fan

The 11-second video shows the crew on location somewhere in Los Angeles, before it pans over to reveal Ventimiglia looking years younger in a black muscle T-shirt as he leans against a vintage-looking brown truck.

Olin posted another video, about six seconds long, showing Ventimiglia in an auto mechanic’s uniform working on a classic black car.

Could it be the same car Jack ended up selling once he discovered he and Rebecca (Mandy Moore) were having triplets (see: episode 11, titled “The Right Thing to Do”)? Sure seems that way, doesn’t it?

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Ventimiglia later posted a pic of himself sitting in the same car, teasing, "Jack way back when."

Are we about to see what Jack’s life was like when he was younger? Could we be seeing Jack and Rebecca’s first meeting? Let those theories commence!

This Is Us
airs Tuesdays at 9 p.m. ET/PT on NBC.

Last week, Ventimiglia surprised an unsuspecting fan watching This Is Uswhile they were filming next door. Watch the adorable moment below.