From OVA 2 of Thus Spoke Kishibe Rohan (JoJo Part 4 spinoff)
I got curious about this because of the copyright-related changes made to the JoJo Part 6 anime (Disney references changed to WB ones) so I asked around and got this.
I then looked at when the manga chapter got released (2008 in Jump Square, 2013 in the manga's first volume) then saw that there are tweets going back to before the volume version came out in Japan referencing it so basically Sailor Moon is canon to the JoJoverse.