The two met in Delhi at the Jawaharlal Nehru Stadium ground during the shooting of Abhinav Kashyap's "Besharam" to discuss the song that Honey would be singing for Ranbir in the film.
And within 15 minutes the twosome was the talk of the entire crew.
When one contacted Honey Singh for details of this unusual friendship, he said: "News travels fast! Yes, I've formed the most incredible friendship with Ranbir. I had gone to discuss our song for Abhinav's film... We discovered many common interests."
Honey found Ranbir to be "as chilled-out as me".
"To be honest, I've been working closely with other Bollywood stars. I am a very open-hearted guy. But I find Bollywood's actor to be extremely cagey. I am typical North Indian. They don't open up that easily. With Ranbir, within minutes we were sharing confidential secrets. Obviously I am not going to tell you what we spoke about," he added.
Honey did let out that they both love fast cars.
"Ranbir and I own the same car with the same number (Audi RB Number 8). We share a lot of common interests. In fact, I am taking him partying in Delhi next week. To be honest before meeting Ranbir, I was wary of star-kids. I find they get everything too easily. But Ranbir is who he is not because of his family but his own talent and good nature. He's self-made, like me," he said.
About their professional partnership, Honey revealed: "Yeah, we'll be working on several songs. But that isn't all. I'm also going to make him sing for me."