They really are an Australian act ─ see their Wikipedia page. The three presenters are actresses ─ they are all gorgeous looking ─ and the near-perfect and accentless North American pronunciation shows that they are indeed making a quite an effort at speaking a flawless North American English. No genuine US American ever speaks like that, because every region of the USA has its own accent, and in some cases, even a dialect, a local vocabulary and local grammar.