Prince Harry and Meghan Markle are celebrating son Archie‘s second birthday on May 6, but this year’s occasion is going to be a little different than the last. Because this is Archie’s last milestone “as an only child,” the expecting couple is going out of their way to make it “super special,” an insider exclusively shares with Closer Weekly.

“They’re staying local in Montecito and are having a pool day and BBQ in their luscious garden,” the source tells Closer ahead of the royal youngster’s birthday bash. “They’re spoiling him with gifts, books, a toy car, jigsaw puzzles [and] a children’s cooking kit.”

Meghan Markle Gives Birth to Baby No. 2 With Prince Harry Son Archie

In addition to the endless entertainment, which also includes “activity games for the garden,” the 36-year-old prince “got a chocolate fountain,” the insider shares, noting Meghan, 39, “left most of the birthday shopping up to Harry this year.”

Considering the Duke of Sussex wanted to go above and beyond for his little man, he made sure to buy “party hats, balloons, candy and a delicious multi-layered birthday cake.” The source reveals Meghan’s mom, Doria Ragland, is also pitching in as she “offered to make the cupcakes.” Despite their strict eating habits, “on birthdays, the Sussexes let their healthy diet slide,” the source adds.

While Harry and the former Suits actress — who announced their pregnancy with baby No. 2 in February 2021 — will be staying in the U.S. for Archie’s birthday, the insider tells Closer that Prince William and Duchess Kate (née Middleton) have already reached out. “William and Kate mailed Archie a gift for his birthday from George, Charlotte and Louis as a nice gesture for their nephew,” the source shares.

Harry and Meghan won’t have their royal family members around to celebrate, but fortunately, “Archie has already made a few little friends in Montecito,” the insider dishes. Though he can be shy at times, Archie “gets so excited when he mixes with children his own age” and is very outgoing. “He’s really come out of his shell. When he wants something, you know about it.”

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Aside from being “an independent, confident and determined child,” the tot “has the cutest personality and is a mix of both Meghan and Harry,” the source goes on. “He’s inherited Meghan’s brains and has an extensive vocabulary for a 2-year-old. He can sort shapes and colors and is already learning the alphabet.”

Archie definitely “has Harry’s sense of humor and cheeky streak” as he’s “such a little character,” but the ginger-haired cutie also knows when to be on his best behavior. “Harry and Meghan are raising him to have impeccable manners and he always says please and thank you,” the insider says.

Most impressively, the source tells Closer Archie is “aware that it’s a special day” and “has more of an understanding of what his birthday” this time around. “Harry and Meghan are trying to teach him to sing to ‘Happy birthday to you … ,’ and he tries to follow along. It’s so adorable.”

With all these amazing qualities, there’s no doubt Archie is going to be the best big brother once baby No. 2 arrives this summer!