Yup, back when Harry Potter and the Sorcerer’s Stone was being filmed for its 2001 release, Julianne Hough got involved with the production as an extra.
At the time both Julianne Hough and her brother Derek were child actors, and they were living in England, where the Harry Potter franchise movies were filmed.
Both siblings appeared in the film, although while Julianne was front and center in Gryffindor, Derek was relegated to Ravenclaw, and he later stole some of his Ravenclaw gear from the set.
As for Hough, she dished to her Instagram followers that she apparently loved flirting with the Weasley twins.