The tot will turn one on Wednesday (May 6) as he and his family spend the lockdown at their new home in California.
And it seems Harry and Meghan are keen to make it as enjoyable as possible for the youngster, despite the coronavirus pandemic restrictions.
According to royal expert Katie Nicholl, Meghan will likely be whipping up a delicious but healthy birthday cake for Archie, as she's an "amazing cook".
He turns one on Wednesday
What's more, the trio are expected to spend much of the day in the pool at their new pad in Los Angeles, where they have settled following their decision to step down as 'senior' members of the Royal Family.
And while social distancing measures might prevent Archie from seeing his maternal grandmother, Doria Ragland, Katie thinks the little one will still enjoy spending time with the two family pooches, who have become his "best friends".
In a chat with OK! magazine, author Katie said: "Meghan's an amazing cook and loves being creative in the kitchen so I think she'll have been busy baking so Archie can enjoy his first taste of birthday cake this week. It will be organic and possibly sugar-free. Something suitably healthy for a one year old.
They're his best friends at the moment.
"If the weather's good, I think they'll be splashing around in the pool too."
Of the family pets, which Katie said are the Sussexes' "saving grace", she explained: "They're extremely good with Archie and he's very used to them. With no playdates in the diary, I think they're his best friends at the moment."
Zoom with the Queen
Discussing gifts the little one would likely receive, Katie said Harry and Meghan "don't spend silly money" on items like toys and clothes. Archie, she explained, has "everything he needs".
But she thinks the pair will welcome gifts for the tot's new nursery. They would also appreciate meaningful gifts, like donations to a children's charity.
And despite Archie now being thousands of miles away from his great-grandmother, the Queen, Katie is sure the two of them will see each other via video call.
She told OK! that Archie would also be video-calling the Cambridge children, who have been "looking forward to seeing how much he's grown".
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