The Oscar-winning actress shared this photo on Instagram a while back. She herself didn't think it was one of her cutest photos as an adolescent. We beg to differ!

This is Reese Witherspoon today. Elegant and still youthful in her appearance.

Kate Beckinsale posted this photo on social media to remember how she used to be as a teenager. The younger Kate appears to be trying on a new bra that Santa gave her for Christmas.

The transformation is impressive, but we stil see that teenager in Kate Beckinsale today.

That smile is unmistakably Jack Black. He may have found this photo awkward, but it was part of his agency portfolio anyway.

And it definitely paid off! Jack Black has been casted in numerous movies and series, making him a firm Hollywood star.

He looks like he's waiting for something. "Have you taken the photo yet?"

Many viewers know him from the series 'Girls.' Andrew or Andy Rannells shared the previous picture media, to show how different he used to look.

Want to make more guesses? Check out the quiz: Who's that kid?

He's a happy teen on the photo, but perhaps not the handsome TV man he would become.

Tony Hale from the series 'Veep' and 'Arrested Development,' among others, looks very different today.

A big change for Heather Graham! This is her somewhat awkward portrait as a teen.

The American actress appeared in 'Austin Powers' and is also among the cast of the new, apocalyptic series 'The Stand', based on a Stephen King novel.

What's new on Amazon besides 'The Stand'? Check out this gallery of 2021 premieres

Michelle Monaghan shared this picture of herself as an adolescent and said that it was not her best ever. We think it's alright though.

Of course, with professional hair, makeup, and the latest fashion, she looks absolutely stunning today.

What was she celebrating? In any case, the photographer caught teenager Olivia Wilde at a moment that she may not have been best prepared for a picture.

See how little she changed! She's really just gotten a little older, nothing else.

America Ferrera may find this teenage picture awkward, but we find it cute.

And just like Olivia Wilde, she hasn't really changed at all.

The boy on the left is Brandon Flynn in one of the lesser poses in his photo collection. It's the same Brandon who would play an part in the ultimate 'teenage angst' series: '13 Reasons Why'.

The actor manages to look even younger as a high schooler in the series than how he looked as a teen in real life.

What a picture this is of Joseph Gordon-Levitt! He says it's not the best he has in his album, but we like it a lot.

This is the actor all grown up and tidy (at a premiere in 2017). He should reconsider long hair, we like it!

We're not sure about the cat in the picture, but teenage Lena Dunham seems to be at ease here.

The actress and writer of 'Girls' has opened up about suffering from OCD and anxiety when she was a young girl. She made a video for the Child Mind Institute in 2017 to help others coping with these mental health issues.

Read about other celebrities living with chronic illnesses

We knew these guys from when they were teenagers. Looking back at their 90s' looks today, we may not be as enchanted as we used to be.

They've returned as a group, and this is how the Backstreet Men look now.

What a picture of Ruby Rose! Yes, she's a featherweight with an interesting haircut, but she already has the beautiful eyes and mouth that we've come to know the actress for.

With completely different hair and a confident smile, here's the adult Ruby Rose. You probably know her from 'Orange is the New Black' or 'Batwoman.'

See more stars who may (or may not) be recognizable from their childhood photos