Somebody had to call in the bribes.

It seems like yesterday that Prince Harry and Meghan Markle tied the knot at St. George’s Chapel in Windsor, but on Monday, May 19, the couple celebrated their seventh wedding anniversary. The Duchess of Sussex marked the occasion by posting some never-before-seen photos of herself with Prince Harry, Prince Archie and Princess Lilibet on Instagram—but another person who took part in the couple’s big day also revealed a rare photo.

Celebrity photographer Alexi Lubomirski, who also took Harry and Meghan’s engagement portraits, shared a TikTok divulging his secrets to capturing the perfect royal wedding photos. The photography pro admitted that it “was scary to say the least” to be asked to take such “historic” wedding portraits.

“Nobody knew I was going to do the engagement pictures, so there was no pressure,” he explained. “With this one, they announced everybody before.” Lubomirski said he’d “constantly get messages on Instagram” ahead of the big day telling him “don’t screw it up.”

Lubomirski and his wife attended Harry and Meghan’s ceremony as guests, since he wasn’t photographing the wedding itself. Afterward, he headed to the Green Drawing Room at Windsor Castle for the formal photos—but not before getting some good advice from a royal nanny.

“Before Meghan came in, I heard the kids, the pageboys and the bridesmaids, and these were young children and of course they were getting bored and misbehaving,” he said. “And one of the nannies said to them, ‘If you’re good, you’re gonna get Smarties!'”

“For some reason that stuck in my head,” Lubomirski added.

Before it came time to take the official portraits, the photographer asked Prince Harry for any advice on photographing the Royal Family—and he said it was all down to his grandparents, Queen Elizabeth and Prince Philip. “You know, they’re very old, they’ve taken so many pictures in their life,” the Duke of Sussex told Lubomirski. “If you don’t get it quickly they’re going to just move out.”

With this in mind, the photographer tried to gather everyone as quickly as possible, comparing the mood to “a Thanksgiving family event when you’re trying to get kids to come in for a group photo.” When they were running about five minutes behind, Lubomirski apologized to Queen Elizabeth and she replied, “It’s not me you need to worry about,” referring to Prince Philip.

But when things got hectic, it was the nanny’s comment that saved the day. “At one point, none of the kids were looking at me,” Lubomirski said. “They’re all running around and I could see the [late] Queen shuffling in her seat. So I suddenly shouted, ‘Who likes Smarties?'”

The line was a hit. “Harry suddenly said ‘me!’ and everyone laughed and smiled,” the photographer recalled.

Lubomirski went on to share some of the portraits he took from the day, including one outtake that didn’t make the cut. In the photo, Meghan and Harry are sitting on the same steps in the castle’s rose garden where one of their official wedding photos was taken, but both the duke and duchess are looking down at their hands.

“It was their first moment as a married couple where they were just alone and there was this sense of relief and beauty and joy and they just slumped on the stairs,” he said.