“Keep Austin weird” is a slogan adopted by the Austin Independent Business Alliance to promote small businesses in this liberal Texas haven. No one took that motto more to heart than billionaire Elon Musk and brother Kimbal Musk, who broke out in their own quirky rendition of “My Little Buttercup” from The Three Amigos at SXSW.

At the conclusion of Elon Musk’s hourlong Q&A session Sunday, where he shared his vision of the future, he was joined onstage by Kimbal in full singing cowboy regalia (guitar and white hat).

Elon Musk warned “this is going to be real bad” before donning a black cowboy hat and bursting into song. Westworld creator Jonathan Nolan, who moderated the discussion, wisely took a pass, standing onstage with his arms crossed.

Check out the video above. For reference, here’s the Steve Martin-Martin Short original: