Beverly Hills sunglasses blonde Nicole Richie

OK, so the slightly frizzy hair is a pretty good indicator that the starlet already finished up her workout, (plus, we already snapped her picture immediately after she left Tracy Anderson's gym on Friday morning), but dayum! The fact that the mother of two looks this hot after sweating her skinny little butt off is something to be proud of -- most A-list reality stars hide behind their towel when we catch them fresh from the treadmill!

So what did Nicole have to say about hacking Khloe and Kim Kardashian's Twitter accounts as an April Fools' Day prank? Nic tweeted, "I DID NOT hack @KimKardashian's twitter! But @KhloeKardashian you were such a good sport. Until next year..." Of course, it looks like someone got into some mischief with Nicole's page, as she added, "SO FUNNY @JoelMadden & @KimKardashian! But I am a mature, classy, & sophisticated adult, & I don't have time for your "foolish" games!"