The Duke and Duchess of Sussex were the guests of honour at the movie premiere, and met with celebrities and fans on the yellow carpet.
But it was Meghan's conversation with Pharrell that raised eyebrows.
"So happy for your union. Love is amazing. It's wonderful," he said.
"Don't ever take that for granted but what it means in today's climate, I just wanted to tell you it's so significant for so many of us. Seriously. We cheer you guys on."
Meghan then replied: "Thank you, they don't make it easy."
The Duchess's comments follow weeks of tension for Meghan, who was mummy-shamed for her parenting skills while holding baby Archie at a polo match last week.