Hilary Duff isn't necessarily the nice girl she plays on TV -- girl's got a mean side, especially when it comes to her ex, Joel Madden and his new GF, Nicole Richie. “[Hilary] can’t believe he’s dating Nicole and thinks she’s a skank,” a source tells Us. When Hil heard about Nic’s arrest, “she asked if Nicole had been coming from Joel’s,” the source says. “She kept saying she never knew Joel at all.”

Maybe this is how Lindsay Lohan felt when Hil stole Aaron Carter from her. Oh, snap!