The 'Cruel Intentions' star split from the fashion designer in September last year after two years together, but she has maintained a close relationship with her ex for the sake of their son Arthur, 23 months, reported Contactmusic.
Blair sparked rumours the former couple had rekindled their romance when she was snapped smiling as she stepped out in Studio City, California, sporting a big sparkler on her left hand, but the actress has been quick to shoot down the claims.