The odds are pretty good that if you have even a passing interest in motorcycles -- or adventures -- you've probably clapped eyes on Ewan McGregor and Charley Boorman's epic travel documentaries Long Way Round and Long Way Down. 

For a while, we've known that the Hollywood star and his pal were working on a third series titled Long Way Up that would see them braving the wilds of South America on their way up to Los Angeles. Apple announced Monday that the series is coming to Apple TV Plus in September, but that's not all.

One of the previous bits of information we had about the series was that instead of using their typical big BMW GS adventure touring bikes, McGregor and Boorman were doing this trip using electrons only -- specifically the Harley-Davidson LiveWire, specially modified for the rough stuff.

We also saw images of prototype Rivian trucks being unloaded at a port near the motorcycles. We suspected -- along with the rest of the internet -- that these would be used as support vehicles during the adventure.

Rivian confirmed via Instagram on Tuesday that two R1Ts took part in the 13,000-mile adventure. Hopefully the series will give some more insight into the capabilities of one of the most hotly anticipated electric vehicles of the last few years.