Godzilla: King of the Monsters brought famous Toho Kaiju King Ghidorah, Rodan, and Mothra into Legendary's MonsterVerse along with many unique kaiju of its own, so there were plenty of Easter Eggs and shout outs showing love to the original Japanese films. Mothra has a pretty notable one especially, and fans were surprised to see Mothra's origins paid tribute to so well.
A major part of Mothra in the original film are her Fairies, the miniature twins Mothra uses to communicate with mankind. They don't appear or operate the same way in King of the Monsters, but there is a set of twins carrying on the tradition in spirit.
In Godzilla: King of the Monsters, Monarch scientist Dr. Ilene Chen (portrayed by Ziyi Zhang in the film) is an expert on the Titan's appearances throughout history and it's revealed that she's actually a twin in a long line of other twins that have been studying the Titans for a long time. The final reference photo sees a pair of twins visiting Infant Island (Mothra's original home) in 1961, the release date of Mothra's debut film in Japan.
In each of Mothra's appearances in the original Toho films, the Kaiju is accompanied by a set of twins. They have different names over each appearance, but their role is to act as the point of communication with humanity. They also summon her with the "Song of Mothra." This doesn't happen in King of the Monsters, but that song does sneak its way into the official soundtrack.
Though the Chen twins do not serve the same purpose as the fairies, one is present when Mothra emerges from its cocoon midway through the film. So this is a subtle Easter Egg for fans that won't throw off new fans of the franchise. It's the kind of attention to detail fans have come to love from the big sequel for sure.
Directed by Michael Dougherty, Godzilla: King of the Monsters is now in theaters and stars Millie Bobby Brown, Vera Farmiga, Sally Hawkins, Kyle Chandler, O'Shea Jackson Jr., Ken Watanabe, Bradley Whitford, among many other talents. The film is officially described as such:
"The new story follows the heroic efforts of the cryptozoological agency Monarch as its members face off against a battery of god sized monsters, including the mighty Godzilla, who collides with Mothra, Rodan, and his ultimate nemesis, the three headed King Ghidorah. When these ancient superspecies, thought to be mere myths, rise again, they all vie for supremacy, leaving humanity's very existence hanging in the balance." You can read ComicBook.com's spoiler-free review of the film here.