What becomes a fat ass most?

Is it the size, the shape, the texture, the ... temperature? Diego Luna did the all-important rear-end research for his latest role in the new Hulu series La Måquina.

On a recent appearance on The Drew Barrymore Show with longtime pal and La Måquina co-star Gael García Bernal, Luna discussed finding the fake butt that fit juuuuuuuust right.

Alexandro Bolanos Escamilla/Hulu

Bernal stars as the titular character, Esteban "La Máquina" Osuna, an aging boxer preparing to enter the ring one last time and Luna plays his childhood friend/manager, the imagee-obsessed Andy Lujan. For the part, Luna had to wear a fake nose, fake lips, and, yes, a fake ass.

"It's very comfortable," Luna told Barrymore of his posterior prosthetics. "It's padded shorts, but they're the right temperature, the right texture. They're firm, but not too firm. I think we managed to get it just right. The others were painful, but that one was just nice."

The Andor star previously spoke to Entertainment Weekly about some of those uncomfortable glutes, calling his fake butt(s) "gigantic" and expressing how happy he was to no longer be hauling those dump-trucks around all the time.

"The trousers had to be tailored for that ass to fit," Luna explained. "But I mean, [Andy] is someone that is just not happy with the way he looks, and not happy with what he sees in the mirror."

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Well, at least people could be happy watching Andy walk away. La Máquina,  Hulu's first Spanish-language original series, is currently streaming.

Check out Luna and Bernal, who also serve as executive producers on the show, gabbing with the best close-talker in the business below.