Ellen DeGeneres becomes a brunette

Hmm, is that a wig?

An April Fool's wig, perhaps? Or a brand-new look for Ellen DeGeneres?

Ever the jokester, Ellen tweeted this photo to her followers on Monday night, saying, "Reese Witherspoon isn't the only one who's gone brunette."

But that's all she wrote.

Witherspoon revealed her new dark look over the weekend when photogs snapped with her baby son Tennessee in Nashville.