The Nantucket Project (TNP) - an annual meeting of the minds focused on 'live talks, short films, and unforgettable experiences' - aims to bring 'thinkers, creators, and performers' together, from a number of different fields.
Musician and activist Moby took to Twitter to announce that the unexpected trip would all be appearing at the event.
He wrote: "No joke, I’ll be sharing the stage at @thenantucketproject with @richroll and @georgewbush, maybe Rich and I can convert GW to veganism?"
Roll, on the other hand, simply wrote that it would be 'an interesting weekend'.
At the event, Roll spoke to his personal transformation - and how he went from addict, to food-addicted lawyer, to the athlete and influencer he is today.
Commentary on the TNP Facebook page said: "Rich Roll - ultra-endurance athlete, author, podcast host and committed vegan - inspired the crowd at #tnp8 with his talk on human transformation and why it's available to us all."
Topics touched on by other speakers include parenthood, the 'me too movement,' and race relations.