When I was a kid I was convinced that emus were called "ostriches." Because come on! "Australia" sounds like OSS-trail-ya, so how could they not have the birds whose name sounds the same. I guess ratite branding was a big thing to my younger self.
It's not clear how closely related ostriches, emus, rheas, cassowaries etc are, and whether they had a common ancestor on the superncontinent of Gondwana. As you can see here, ostrichese and emus don't look that much alike. Emu necks are much fluffier. They do dance/play together well, considering both birds are somewhat volatile to begin with