The story behind the page boy’s reaction in THAT viral royal wedding photo is too cute

He was one of the star of one of the funniest photos of the royal wedding.

And it's now emerged what exactly caused 7-year-old Brian Mulroney, one of the page boys holding Meghan Markle's veil, to break out into a very, very excited grin as he entered Windsor Castle. His dad, Ben Mulroney (who is married to Meghan's best friend, Jessica), explained the reason behind his son's memorable expression on Canadian morning chat show, Your Morning.  He said:

"I asked him, and he said he'd never heard a trumpet before. "I think when he walked in, he saw all the people there, and the flowers, none of that was there during the rehearsal."

Okay, well that's definitely understandable. And beyond adorable. Brian and his twin brother, John, were two of the page boys for the wedding, while their 4-year-old sister, Ivy, was a bridesmaid. Their dad, Ben, explained that the kids involved in the wedding party had actually had a chance to get to know each other a bit before the big day to put them at ease. He added:

"There had been so much talk about getting it right with the rehearsals and these kids are so young. "There was a lot of worry that this wouldn't get done right, but they're having so much fun with it. "And that, to me, was the thing that gave me the most pride was that we didn't put so much pressure on them that this wasn't joyful for them. "It was pretty darn joyful."