There's very actors who'd be as willing as Josh Brolin to have someone interviewing them open up their shirt, let alone have them draw chest hair on with a magic marker on live television.
Then again, not everyone is Josh Brolin and Stephen Colbert - so there's that. The actor was on the Late Show last night to talk 'Sicario: Day Of The Soldado' and naturally ended up discussing how he shaves his chest and demonstrating it for all to see and then talking about Thanos and how he's nothing at all like Donald Trump, but then proceeding to read out tweets in his voice anyway.
To be fair to Brolin, Thanos sounds just like him so it's not as if there's any real difference in the two. All you've got to do is pretty much just lower the voice slightly and speak more slowly and he's got Thanos. The real trick would have been doing Thanos' lines as Trump. It's a long interview, and the Thanos bit is right at the end, but you've also got Brolin and Colbert discussing the utterly horrific situation going on at the Mexican-US border - which ties in with the setting for 'Sicario: Day Of The Soldado'.
Wow, that's a long sentence. Here's the video.