Diva-in-chief. Photo: Kevin Mazur/WireImage Okay, yeah, we know: You won’t believe it until you see it . But Beyoncé is reportedly appearing with Kamala Harris at a rally in Houston on October 25. The Washington Post had the news first, instantly giving us déjà vu from all those super-secret surprise-guest rumors from the DNC back in August. This time, though, it actually looks a bit more real — nearly every outlet following the Harris campaign has confirmed the story. (If any campaign sources