Kanye West and fellow rapper Kid Cudi have buried the hatchet and are working on a top-secret project in Japan, Page Six has exclusively learned.

West — who’s been keeping a low profile since his breakdown last year — has been holed up in a studio with Cudi, who checked himself into rehab last fall for “depression and suicidal urges.” Around the same time, West was hospitalized for a reported “nervous breakdown.”

According to a source, the new project is so secret, “they’re going to drop some crazy collaboration out of the blue,” an insider told us. “They’re going to drop some surprise project on everybody. They’re recording it now.”

They’re keeping the lid so tight that “nobody knows what it is — or what it sounds like . . . There are no professionals in the room. It’s just Cudi, Kanye and an engineer. They’re recording together in Japan.”

West and Cudi were in an infamous rap feud last year when Cudi — who’d already left Kanye’s G.O.O.D. Music record label — dissed West on Twitter, and West responded on his “Saint Pablo” tour by saying, “I birthed you . . . I’m so hurt. I feel so disrespected. Kid Cudi, we’re two black men in a racist world.” But West later said, “Kid Cudi is my brother . . . The most influential artist of the past 10 years.”

A source close to West explained that the duo’s feud “went away pretty quickly. It was likely something that was lingering, but not as serious as it seemed. Kanye’s always airing out whatever he’s thinking onstage, but they’ve always been close.”

Buzz of a collaboration began in July, when the rappers were spotted together in LA with Plain Pat, who has managed and produced for both artists. Artist Takashi Murakami posted a photo of the duo visiting his studio last week. “They’re rolling together all over,” said a hip-hop source.

In May, Page Six reported that West was recording on a remote Wyoming mountain to find his “creative groove.” He’s also been seen hitting the studio with rap group Migos. Cudi just announced 27 dates for his own upcoming tour.