Inside the many love triangles of Harry Styles, Olivia Wilde and Emily Ratajkowski

It’s definitely “Love on Tour” for Harry Styles after he was caught kissing Emily Ratajkowski in Tokyo.

The two were seen openly drooling all over each other on a street this weekend after Styles, 29, finished the Asia leg of his tour.

And while Ratajkowski and Styles’s ex, Olivia Wilde, have palled around recently, an insider told Page Six that the model likely wasn’t bothered by hooking up with her “friend’s” sloppy seconds.

“I don’t even think she would be a thought for Harry and Emily,” the insider said.

It’s the third time Styles and Wilde, 39, have been involved in a love triangle, after rumors of Styles-related jealousy and tension between Wilde and Florence Pugh on the set of “Don’t Worry Darling” — and after rumors that Styles came between Wilde and her ex, “Ted Lasso” star Jason Sudeikis.

The weekend’s passionate embrace between Styles and Ratajkowski comes four months after the singer’s split from actress and director Wilde.

A source who knows Styles confirmed to Page Six that he and Ratajkowski have known each other for years, adding: it’s “very casual .. .they’re having fun. Harry liked Emily years ago.”

Don’t be surprised to see even more of the fun-loving pair now that Styles has a month off to relax before going back on tour in Europe.

But who knows what will become of Ratajkowski’s friendship with Wilde now.

Only two weeks ago, Wilde and Ratajkowski, 31, were pictured sipping cocktails and chatting with British model Adwoa Aboah at the March 12 Vanity Fair Osars soirée.

In November, Ratajkowski went public in support of her friend Wilde, in a cover story for Elle UK.

The model spoke out on Wilde’s controversial directorial debut in “Don’t Worry Darling,” as Wilde was accused of having a falling-out with star Pugh over the Styles’s affair — and video surfaced of referring to Pugh as “Miss Flo,” which some fans saw as demeaning.

Ratajkowski said, “In the past year with Amber Heard and Olivia Wilde and the craziness of putting them in this box as if they’re monsters or witches … There’s nuance to it, but when you see the way that the whole world reacts to women, it’s really hard not to want to go to an extreme side of it. I feel very protective.”

When Styles performed at the Accor Arena in Paris in July, Ratajkowski stood next to Wilde in the VIP section, both of them singing along to Styles’ performance “Sign of the Times.” Wilde spent much of last year touring with her then love.

Page Six is told, however, that Ratajkowski, who hosts an Apple podcast called “High Low with Em Rata” produced by Sony Music, was invited to the concert by Sony bigwigs. “Emily didn’t go with Olivia,” said the Styles source.

In November, Page Six confirmed Styles and Wilde were “on a break” and had put their near two-year long romance on pause.

But a Hollywood insider who knows Wilde told us: “That was a gentle way of saying it’s over … Harry and Olivia are not getting back together.

“Olivia doesn’t have anything to do with this situation.”

It was certainly a situation when Wilde and Sudeikis’ former nanny spoke out about their love triangle with Styles.

According to Erika Genaro, Sudeikis only discovered Wilde was seeing Styles when he found messages between them on her Apple watch.

“When I saw Olivia holding hands as a couple with Harry in the news, I was shocked, as just a month before, when we were in LA, she was sending Jason messages saying she loved him,” Genaro told the Daily Mail.

The nanny claimed that a devastated Sudeikis blocked Wilde’s car with his body, that Wilde gave up her dog to spend more time with Styles, and that Sudeikis was crushed when Wilde left him and their two kids to have dinner with Styles — taking her special salad dressing with her

Genaro also alleged that Pugh was seeing her “Don’t Worry Darling” co-star Styles before he started dating Wilde, and that Sudeikis had told her that “Flo was f—ing Harry.”

Multiple sources have confirmed to Page Six that Pugh and Styles had a very brief fling on set.

This past weekend, soon after the photos of Styles and Ratajkowski came out, Wilde and Sudeikis were seen chatting together at their kid’s soccer game — despite her having lashed out at the “Ted Lasso” star in a court filing last week amid their custody battle, claiming he was trying to “litigate her into debt.”

Page Six has reached out to Wilde, Styles and Ratajkowski for comment.

Meanwhile, Ratajkowski has been enjoying a string of high-profile flings since her split from husband Sebastian Bear-McClard last summer, after four years of marriage, amid allegations he cheated on her.

She was linked to Brad Pitt in October, although sources were quick to stress they were not officially dating, and she had some very public dates with Pete Davidson and comedian Eric André, including joining each courtside at Knicks games.

André posted a nude photo of himself and Ratajkowski for Valentine’s Day before she allegedly gave him the push.

Styles confessed to having a crush on the model back in 2014.

During an Mexican TV interview with his former One Direction bandmates, the singer was asked who his celebrity crush was.

“Emily Ratajkowski from ‘Gone Girl,’” he said in the clip from Telehit, albeit slightly mispronouncing her name.

As for the future: Styles — who was also recently linked with Australian blogger and influencer Yan Yan Chan after “sliding into her DMs” — finishes his tour in Lisbon, Portugal in July. He is set to take a rest, but does plan to act more.

Watch out for him in the Marvel universe after he made a post-credits scene in the 2021 movie “Eternals” as Eros, the God of Love and Sex, aka Starfox, brother of Thanos.

In January, Marvel executive Nate Moore told Deadline’s podcast “Crew Call”: “We certainly didn’t cast Harry for a tag.”