The actor, who starred as Harry’s nemesis Draco Malfoy in the film franchise, shared the clip on his Instagram on 1 October.
It features Felton, Watson (Hermione Granger), and Daniel Radcliffe (Harry Potter) wearing their Hogwarts robes on the set of the first film, Harry Potter and the Philosopher’s Stone.
In the video, Watson and Felton play the “hand slap” game – where the second player must slap the first player’s hands before the first player can pull them away – as Radcliffe watches.
“Champion #Slytherin,” Felton wrote in the caption, suggesting he won the game.
Watson also commented, saying she did her best to beat Felton: “I’d like to point out that I did go on to win,” she wrote.
The pair were recently pictured on holiday together in South Africa, having formed a close friendship after filming the eight Harry Potter films.
Felton, 31, shared a photo of him teaching Watson, 29, how to play the guitar, and captioned the image “quick learner”.
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