If all goes according to plan, Maezawa and his artist crew may become the first people to fly SpaceX's Big Falcon Rocket - a new launch system that's being created to colonize Mars - and also the first-ever private lunar tourist in history. He is the first to book a trip as a private passenger with the commercial space company for a voyage that hasn't been attempted since NASA's Apollo missions ended in 1972.
"All of that noise in the background, that is the sound of unbelievable things happening", NASA astronaut Victor Glover said.
"Finally I can tell you that I have chosen to go to the moon" with artists, Maezawa said.
"Why do I want to go to the moon?".
He's planning to take six to eight artists with him, and he won't be charging them for the ride. The goal of Maezawa's project is for the artists to be inspired by the journey and create art about it when they go back to Earth.
Maezawa would not reveal how much his ticket had cost him - but said it was considerably more than what he had spent on the Basquiat painting. He lives in Houston and has visited the SpaceX headquarters in California. "Please don't say no", Maezawa said.
Of course, the craft is very far from completion and Musk has repeatedly set aspirational timelines for its development that never panned out, so this is all more or less conceptual.
The BFR is central to SpaceX's plans of eventually putting people on Mars for the first time, but first of all, they need to prove that the thing actually works.
However, Musk said that rocket would not be certified to carry people, which ruled out a round-the-moon trip on a Falcon Heavy.
With SpaceX, Amazon.com founder Jeff Bezos' Blue Origin and entrepreneur Richard Branson's Virgin Galactic battling it out to launch private-sector spacecraft, Maezawa will join a growing list of celebrities and the ultra-rich who have secured seats on flights offered on the under-development vessels.
"If I'm going to go to space, I'd rather go as far as I can", he said.
Maezawa made his fortune by building up Start Today, an e-commerce business that includes a popular online clothing site in Japan.
The 42-year-old is worth an estimated $2.9 billion and has been known to drop unfathomable amounts of money on art - including a Jean-Michel Basquiat purchase in 2016 for more than $57 million.
The mission is slated to launch as soon as 2023, though Musk said he can't be sure about that timeline yet.
The BFR is a long way from reality and Musk himself says he's "not 100 percent certain we can bring this to flight".
At the time, SpaceX was to have used its heavy-lift Falcon Heavy rocket and the crewed version of the existing Dragon capsule.
SpaceX has said it views space tourism as "an important step toward enabling access for everyday people who dream of traveling to space".
Next year, SpaceX - which has received billions in NASA funding to ferry supplies to the ISS and build a crew vehicle - hopes to become the first private company to send astronauts to the space station.
Elon Musk/SpaceX via TwitterA Sept. 2018 rendering of SpaceX's Big Falcon Rocket launching through the cloud tops and toward space.