Prince Harry and Meghan Markle's Son Archie Receives Sweet Birthday Gift and They React

The eldest child of the Duke and Duchess of Sussex turned 4 on May 6.

Prince Harry and Meghan Markle were delighted by a surprise birthday gift for their son. In honor of Archie's fourth birthday last month, the owners of Mad Dogs & Englishmen Bike Shop, one of whom is British, decided to hand deliver a bike to the tot's home -- a gesture his parents readily expressed their appreciation for.

The Montecito, California, store, which is co-owned by Jennifer Blevins and Martin Watson, revealed the Sussexes' gesture on Instagram, sharing a photo of the thank you note they received after gifting Archie a bike.

"On behalf of Prince Harry and Meghan, The Duke and Duchess of Sussex, please accept their sincere thanks for the thoughtful gift you sent to Prince Archie for his fourth birthday," the thank you note read. "The bike has brought much joy, and is most appreciated by the family. They asked that I convey their gratitude at the lovely surprise."

In an interview with People, Jennifer explained that her British-born partner wanted to celebrate Archie's big day with a special present.

"He went and he got one of our little specialized kids' bikes -- they're really nice little bikes -- and he's like, 'This one's perfect, it's got training wheels,'" she told the outlet. "And so he went and got some birthday balloons, and he got some flowers for Meghan and a birthday card, and he said, 'OK, I'm gonna bike over and take it to their house.'"

When Martin got to the couple's home, he was stopped by security, whom he told, "I'm just a British business in town that wanted to give Archie a gift."

After running a security check on Martin, security allowed him to leave the present. Just a month later, a courier hand-delivered the thank you note from the couple.

"A courier came by our little shop on Coast Village Road, and he dropped off that letter," Jennifer said. "I was making a joke, I said, 'It better be a thank you letter,' and it really was! I wasn't expecting that. I had no idea. It was so thoughtful because, you know, they took the time to write something personal and not just a generic thank you."

Jennifer noted that she, Martin and their staff found the gesture to be "very sincere," and expressed her hope that the bike continues to bring joy to the Sussexes in the years that follow.

"His little sister, Lili, can enjoy it too as she grows," Jennifer said of the couple's 2-year-old daughter. "It'll be one that both of them like."

As for Lili, she celebrated her second birthday on June 4. Her special day was not publicly marked by the royal family, with a source explaining to ET, "It has never been protocol to share formal birthday wishes for non-working members of the royal family or their children on the official channels. Any such birthday wishes would be shared privately."

However, royal expert Katie Nicholl told ET that the lack of birthday love for Lili could be viewed as a "snub."

"I think the fact we didn't see any birthday wishes to Lilibet is unusual," Nicholl said. "The palace is saying that this is not a tradition of wishing family members a happy birthday on social media -- that might be true but certainly we have seen them extend wishes on social media and it does feel that this might be something of a snub to Princess Lilibet."