Amber Heard Elon Musk Go Out On a Line for Me

4/23/2017 4:13 PM PDT

Amber Heard & Elon Musk Go Ziplining Down Under with His Kids

Elon Musk and Amber Heard strapped up and held on tight ... for a little semi-extreme fun in Australia.

The couple went ziplining in the Currumbin Wildlife Sanctuary on the Gold Coast. The actress and Tesla honcho had a lot on the line here, and not just because he was trusting his multi-billion dollar ass to a safety harness.

Two of Elon's 5 sons came along, so Amber had the added pressure of being dad's cool gf. She probably scored some bonus points, since she's Down Under to shoot "Aquaman" with Jason Momoa.

Looks like the couple -- coming up on 1 year together -- had a good time. Still, we gotta say ... no one, not even Elon with his riches, looks good in those helmets.

It's just a thing.