Inside sources close to the show have just confirmed to me exclusively that Sophia Bush is dating her Tree Hill costar James Lafferty. "They're. Couple has been secretly dating for over three months, a source tells E! News. Apparently, Sophia Bush is a fan of coupling up with her co-stars. for six years, but the couple called it quits for good back in February Sophia Bush plays Erin Lindsay on Chicago PD and was dating co-star For five months in , she was married to her One Tree Hill co-star.