Derek Houghis coming clean about a bit of youthful thievery.

“Did you know [Julianne Hough] and I were in the firstHarry Potterfilm?”

he wrote in the caption of a recentInstagrampost.

DEREK HOUGH and Harry Potter cast

Derek Hough and ‘Harry Potter and the Sorcerer’s Stone’ stars Daniel Radcliffe, Rupert Grint, and Emma Watson.Disney/Eric McCandless; Warner Brothers/ Everett

He wrote that it was “incredible to be part of such a historic moment.

Just a little holiday magic and nostalgia to share with you all.

Hough recalled the experience ofhisHarry PotterdebuttoEntertainment Weeklyin 2018.

Harry Potter and the Sorcerer’s StoneDerek Hough (left) and Emma Watson

Derek Hough and Emma Watson in ‘Harry Potter and the Sorcerer’s Stone’.Warner Bros. Pictures

“We were at Pinewood Studios for three months,” he said.

“We attended school in these trailers, and then we just messed around and got into trouble.

We’d have dance-offs during breaks in our full robes.

We’d battle it out in between takes!

I was a Ravenclaw.

Since I was a blond kid, I would be a stand-in for Draco Malfoy.

That was my claim to fame!”

We pass in the hallway.

I was holding an owl.

That’s my big moment.

As for his sister, “Julianne got to be in the Quidditch match scene.

She had a crush onDaniel Radcliffe.

She wrote him a love letter and sent him a teddy bear.

They were like 12 years old.”

The Houghs are now Emmy-winning media moguls not bad for a couple of Ravenclaw and Gryffindor extras.