I posted it in another reply to you just below. He’s never been on video saying exactly what you said but he’s been quoted in articles/newspaper interviews. Snopes has a good summary with links to the publications.
https://www.snopes.com/fact-check/patrick-stewart-on-galaxy-quest/
And he cannot lie.
https://youtu.be/X53ZSxkQ3Ho?si=_9ViEQ2atbE8-4x4