Sir John is sounding off on the bold makeup look he created on Beyonce for the 2016 Met Gala.
The makeup artist sat down with ET's Kristen Gill where he responded to the fans on social media who weren't keen about the pop star's smoky eye look.
"I had a bad year where I got dragged to hell! But I learned from it, so I don't think there's any such thing as a mistake if you can learn from it and at the time I liked it, my client liked it," Sir John said.
He explained, for him, makeup and beauty is all about communicating an empowering vibe.
"When I look at somebody like Beyonce and she's performing at Wembley Stadium or Stade de France in Paris in front of 90,000 people, I just know that this is one of the most important liners I need to do or most important smokey eyes that I need to have happen. So I'm just inspired by everyday women."
In addition to Beyonce, the makeup maven has glammed up the famous faces of Serena Williams, Karlie Kloss, Priyanka Chopra and Joan Smalls, and many of his high-profile clients are expected to attend this year's Met Gala. Although he wouldn't spill any secrets, he did reveal the process of the prep.
"So all the women that I'm working with, they start to send over sketches of the designers. So everything is like, OK there's a theme this year and I think the theme is called 'Camp,'" he explained. "But some people are putting their own twist on it. I can't say who they are. And so it's one of those things where we want to make sure that they hit the mark. When I say hit the mark, hit the red carpet and the women who I'm working with, just to get all the life and all the attention of all the press there and make a moment."
"You really want -- whoever your makeup artist is, you want to create a moment where the next day every beauty editor is talking about it," Sir John continued. "So that's the goal. So whenever you see a Met Ball and I'm gonna do it, I'm only going to attach myself to people who I know are gonna go and just kill it on the carpet."
Watch ET's full interview with the pro in the video above.
Catch up on the most iconic looks from Met Galas past: