*Herbie Hancock is referring to his forthcoming album “The Imagine Project,” due June 22, as “the hardest record I’ve ever made.”

The Grammy-winning keyboardist tells Billboard.com that actually playing the 10 tracks “was easy compared to what it took to put (the album) together,” which included gathering such guest performers as India.Arie, Chaka Khan, John Legend, Seal, Pink, Dave Matthews, Toumani Diabete, Wayne Shorter and others.

Also, recording sessions took place in several countries such as the U.S., India, England, France, Ireland and Brazil. “Every song on the record was like putting a while new album together,” notes Hancock, who worked on the album with Larry Klein, co-producer of 2007’s Grammy Award-winning “River/The Joni Letters.” “It’s that kind of experience. You had to completely retool for each song. Normally you don’t have to do that.

“But I like the fact that everything on the record is different from everything else. It’s in keeping with what’s being practiced today by the general public, which is that people buy songs. In the past you had to buy whole albums; now you can buy song by song, so people buy what they want and put their own compilation in a way. But this is really like a compilation in a way, and I think it’s a good thing.”

“The Imagine Project” includes a version of John Lennon’s “Imagine” with Beck, Pink, Seal and India.Arie, as well as the Beatles’ “Tomorrow Never Knows” with Matthews. Khan, Shorter and Anoushka Shankar teamed up with Indian musicians for the Klein original “The Song Goes On,” while Diabete, the Chieftains, Lionel Loueke and Lisa Hannigan were part of Bob Dylan’s “The Times They Are A’ Changin'” and Legend and Pink joined forces for Peter Gabriel’s “Don’t Give Up.”

“It’s a record that’s basically about peace,” explains Hancock, crediting his attorney with inspiring the concept. “To me the path towards peace is through global collaboration, so the heart of this record is the idea of making a global record or an international record, in multiple languages and in a variety of places.”

The various sessions for “The Imagine Project” were filmed and will become the source material for a documentary and web-based applications, possibly including a site that will allow fans to remix tracks from the album. Hancock also plans to incorporate the footage into his concerts this year, where he’ll dedicate a portion of the shows strictly to the album and include the guests via videos synced with the live band “so that it’s possible to take people on a real journey into the music,” he says.