Stranger Things star Millie Bobby Brown now looks very grown up

Millie Bobby Brown in Stranger Things. Photo / Supplied.

She burst to worldwide fame playing the mysterious, shaven-headed Eleven in Netflix's hit series Stranger Things.

Just three years later, and young actress Millie Bobby Brown — now 15 years old — is virtually unrecognisable from the character that made her famous.

The English actress looked very glam — and very grown up — as she walked the red carpet for a Stranger Things season 3 screening in New York this week.

Yep, that's Millie Bobby Brown. Photo / Getty Images.

Here's Brown as she appeared in Stranger Things season 1:

Millie Bobby Brown as Eleven (left) and in New York this week. Photo / Getty Images.

And here's Brown in August 2016 during publicity commitments for that first season of the show:

August 2016...and November 2019. Photo / Getty Images.

It's quite the glow-up for the young star, who revealed last month that she was upset with Stranger Things' recent season 3 finale.

Brown admitted the decision for Joyce (Winona Ryder) to leave the town of Hawkins with her in tow sent shockwaves through the cast.

"I was pi**ed. I read the script and I was like, 'What, how is this even possible? Why are they moving away?'" she told Elle Magazine.

Brown said the departure struck a nerve as it made the adolescent stars of the show ponder how they would feel when the show wrapped and they no longer worked together.

"I don't know, I just felt really against it. When we were filming it, all of us kids said to each other, 'So how are we all going to cry?' Because we don't really cry in front of each other very often," she went on.

"I usually am the one who's crying in every single scene, and the kids have to deal with me listening to (sad) music, and they're like, 'Oh God'.

"I thought, 'Are we all going to go off and listen to music?' And then one of the kids was like, 'Imagine if we have to do this for real one day'. And we were like, 'What do you mean?'

"And they were like, 'What if, when Stranger Things is over, we'll all have to say goodbye to each other and like this is it'.

"And we all started crying and then they rolled camera and said action. And that was it. We all started saying goodbye to each other. We felt too real."