Yes, Beyoncé has starred in a few movies. So has Prince. That doesn't make them actors. It makes them musicians who have tried to parlay their popularity into a different medium. And it's never really worked.
It's one thing for Bey to play the sassy comedic counterpart to Mike Myers' Austin Powers. It's another thing to ask her to take the lead in Obsessed, which was intended to be a sexy thriller co-starring the immensely talented Idris Elba as her male counterpart. (He once remarked that kissing her was "weird.")