Bollywood actress Vidya Balan will tie the knot with Siddharth Roy Kapur, managing director - Studios, Disney UTV, in Mumbai tomorrow. The actress opted for a private mehndi ceremony at her Khar residence on Wednesday night. It was attended by her family members and veteran actress Rekha. A wedding reception will be held in Chennai on Saturday. If the grapevine is to be believed, the nuptials will be conducted both in Punjabi and south Indian styles.