Watch Karen Gillan Shave Her Head, Sing Sinéad O'Connor

Nothing compares to this video of Gillan chopping off all her hair.

Zoe Saldana went full green for "Guardians of the Galaxy," Chris Pratt gained a six-pack, and Vin Diesel even turned into a tree, but no one was braver when it came to changing their signature look for the movie than Karen Gillan, who shaved off her famous red locks to play the bald villainess Nebula.

Until today (September 1) we were only able to guess what this process was like for the erstwhile "Doctor Who" star, but now a video has emerged of Gillan bravely going where no Companion has ever gone before -- to bald-lady land.

"Oh, it's happening! It's really happening to me!" the Scottish actress says as her anonymous hairdresser takes the first snip. "Everything's looking a little... tufty on top."

Pretty soon after the buzzer comes out, and Gillan basically goes through every stage of hair-grief as her gorgeous tresses hit the floor.

"That's how easy it is, just to get rid of all your hair!" she exclaims.

Check out the full video of Gillan losing her hair -- and maybe her mind a little, as she sings Sinéad O'Connor to the Internet -- below!