(CNN) -- Chris Hadfield has conquered space. Now he's conquering the Internet, too.
A video of the Canadian astronaut singing David Bowie's "Space Oddity" from the International Space Station has been zipping around the Web at light speed since it was posted Sunday. The five-minute clip features Hadfield singing a modified version of the tune and strumming an acoustic guitar while floating through a space module, more than 200 miles above the Earth.
By Monday afternoon, it had more than 1.8 million views on YouTube, 3,000 comments on Reddit and was being widely shared across social networks.
Hadfield already was something of a social media star, with 260,000 fans on Facebook and more than 825,000 followers on Twitter. During his five months aboard the International Space Station, he has posted numerous photos and videos of himself preparing meals, brushing his teeth and explaining how to vomit in space.
But the elegant "Space Oddity" video, reportedly months in the making, may rocket him into a higher orbit. Hadfield's earnest voice and unique perch in space brings a moving immediacy to Bowie's verses, and when he sings, "I'm floating in a most peculiar way" while actually floating, it's a powerful moment.
Because Hadfield's vocals and guitar were recorded on the space station (and mixed with supporting tracks by Emm Gryner, a Canadian musician who once sang backup for Bowie), some observers are calling it the first music video made in space.
Commenters on Reddit praised the video's simplicity and genuineness.
"The floating guitar is really floating, it's not some computer animation or trickery. The Earth turning behind him in the windows is the real deal. That's us, that's our blue dot, not some stock image, or animation ...," wrote one Redditor. "The video has none of the Hollywood fakery we are used to. Its power comes from this authenticity."
Hadfield took a few liberties with the lyrics of the 1969 Bowie song, which became a hit upon its 1973 rerelease. In the original song, Ground Control loses radio contact with the astronaut, Major Tom, implying that the mission has failed. But Hadfield omits that part.
Bowie himself acknowledged the video, tweeting, "CHRIS HADFIELD SINGS SPACE ODDITY IN SPACE!"
The 53-year-old Hadfield launched aboard the Russian Soyuz spacecraft in December and in March became the first Canadian to lead a spaceship as commander of the International Space Station. The video clip was a farewell of sorts: Hadfield, Soyuz Cmdr. Roman Romanenko and Flight Engineer Tom Mars landed safely in their Soyuz spacecraft Tuesday in Kazakhstan as scheduled, according to NASA.
One Reddit commenter may have spoken for many when he wrote, "You'd better freakin' make it safely or this video will be the biggest tear-jerker on the Internet."