I'd say that it's probably a fairly well known song. Even my dumbass Japanese friends who don't really like music have heard of it. It's called Cosmos by the way.
One of my otaku friends recently pointed out to me that this Louis Armstromg impersonator, who some might find racist, is veteran anime voice actor Koichi Yamadera. AKA the voice of Spike Spiegel. Anime will never feel the same.
^ If only they would take the Kingdom Hearts style world hopping to the next level and instead of generic city and desert worlds made him visit the worlds of popular Nintendo(and if they can afford it Sega too) franchises of the past I would be in nostalgia heaven. Mario Odyssey does look great as i...