High-stakes international diplomacy can take on many forms: Hardscrabble bilateral negotiations. Lavish state dinners.

And, in 2017, a personalized video message from a screwball Japanese comedian to Ivanka Trump and her daughter, Arabella.

The story of how the Japanese Embassy in Washington rushed to produce the surprise greeting from performer Pikotaro — which was the big reveal at last week's annual cherry blossom reception at Ambassador Kenichiro Sasae's residence — illustrates the lengths to which foreign diplomats are courting President Trump's daughter and son-in-law, Jared Kushner, a senior White House adviser who has taken on an outsize role in foreign affairs.

Privately, Japanese officials say Pikotaro, and his viral song “Pen Pineapple Apple Pen,” helped break the ice between Trump and Prime Minister Shinzo Abe during their first meeting at Trump Tower last November. But before we make any grand assessments of how foreign capitals might rethink their approaches to relations with the White House, it is probably best to start at the beginning.

The beginning involves Justin Bieber.

It was the pop star who helped turn Pikotaro's song, known by its abbreviation “PPAP,” from a domestic hit in Japan to a global sensation: Bieber posted it on Twitter in September for his 88 million followers.

The video features Pikotaro, whose real name is Daimaou Kosaka, 43, dressed in a leopard-print, disco-era pantsuit with matching — er, clashing — scarf and chanting a play on words involving the song's title while doing a little two-step to a dance-hall beat.

Pikotaro is sometimes compared to South Korea's Psy, whose “Gangnam Style” remains the most-viewed video in YouTube history with 2.8 billion views. Pikotaro's not quite at that level, but he's doing well: Various versions of “PPAP” have been viewed, cumulatively, several hundred million times.

In any case, one of those who watched it was Arabella Kushner, 5, whose mother couldn't resist filming a clip of her reenacting the video in bed — then posting it on Instagram with the disclaimer: “Apologies in advance — this may be stuck in your head all day #PineapplePen.” This was one week after Ivanka's father had won the U.S. presidential election.

The pint-size Piko scored an impressive 1.2 million views of her own.

Three days later, Abe, on his way to Peru for the Asia-Pacific Economic Cooperation forum, stopped first in New York to pay homage to Trump at Trump Tower — the first foreign leader to offer his congratulations to the president-elect in person. Abe had a lot at stake — Trump had denounced Japan's trade practices and threatened to pull back on the U.S. military partnership if Tokyo did not pay more for the alliance.

It has been well-reported that Abe presented Trump a gold-plated golf club worth $3,755. What has gotten less attention is that the prime minister apparently showed Trump the Pikotaro video during their meeting and explained the connection to Arabella, according to people familiar with the meeting. Ivanka Trump and Kushner both were present at the meeting, raising eyebrows among some foreign policy officials in Washington who wondered whether it was inappropriate of the president-elect to include his family.

Trump reportedly got a kick out of the whole thing, the sources said.

Fast-forward to last week at the Japanese ambassador's elegant residence set off Nebraska Avenue in Upper Northwest Washington. It was there, at the annual celebration attended by the National Cherry Blossom queen and princesses, that Ivanka showed up with Arabella and son, Joseph, 3, in tow.

Sasae had also invited Kushner, but he was on an official government visit to Iraq. Behind the scenes, the embassy had spent two weeks rushing to orchestrate a surprise by inviting Pikotaro to fly to Washington for the event.

It might seem like a lot of effort, but the Japanese aren't the only ones courting Ivanka and Kushner, or Arabella for that matter. The family attended a Lunar New Year reception at the Chinese Embassy in February. And she posted a video that day of Arabella playing with a paper lion puppet and singing in Mandarin. That video has scored 1.7 million views. Arabella later reenacted her performance for Chinese President Xi Jinping and his wife, Peng Liyuan, during Trump's two-day summit with Xi at Mar-a-Lago in Florida last week.

Pikotaro was unable to make it to Washington, citing a scheduling conflict that somehow was more important than meeting the president's daughter in person. But he agreed to make a short video welcoming them and all the other attendees to the reception.

“I hope you are enjoying the National Cherry Blossom Festival 2017 — yeah!” he says in English, before switching to Japanese. He then recreates his hit song, substituting special lyrics celebrating the U.S.-Japan bilateral relationship. “Best-pen friend,” he concludes. The embassy played the video on a big-screen television in a cavernous reception hall with giant shoji screen doors. Ivanka and her children watched from the front row.

After watching, Ivanka and her kids toured another room where Japanese traditional toys such as otedama (bean bags) and kaleidoscopes were displayed. She also spoke with Japan's Cherry Blossom queen, Yuki Shimono; Arabella was assigned as one of the honorary junior princesses of the festival, before the family departed after about 45 minutes.

The event scored widespread media coverage back in Japan. Kyodo news service gushed that Ivanka's presence stood as a “bridge” for bilateral friendship, and the NHK public television network noted that her prior appearance at the Chinese Embassy showed that there's a “growing interest how much she might show her influence in the diplomatic field as her presence in the administration is increasing along with her husband Mr. Kushner. "

As for the White House, there has been no comment about Pikotaro's role in international relations. But Trump and Abe, who golfed together at Mar-a-Lago in February, have by all accounts hit it off swimmingly. An aide to the president did not respond to an email asking for comment about the comedian's role or whether Arabella is still a fan of the song or has moved on to other viral videos, as the youth are wont to do.

Yuki Oda in Tokyo contributed to this report.