Resembling a Mary Poppins figure in tweed, the French YouTuber and comedian Marie S'Infiltre - real name Marie Benoliel - stood up and boldly walked on to the runway.
With a theatrical nod to confused spectators Benoliel then started to strut down the rooftop runway with all the other models.
The catwalk crasher moved so quickly that Chanel's bewildered security team didn't have time to catch up.
However, Hadid who was already on the runway blocked Benoliel's path, and along with other models, escorted her from the catwalk.
Benoliel has done this before, according to her YouTube channel, on which she posted the Chanel stunt.
She previously managed to get onstage at an Etam show with Cindy Bruna in lingerie.
Benoliel's social media name of Marie S'Infiltre roughly translates from French as "Mary gets inside".