In August and October 1999, Khanna performed in the Awesome Foursome concert held at the Shah Alam Outdoor Stadium, Malaysia and the Magnificent Five concert at Birmingham, England. Juhi Chawla, Shah Rukh Khan and Salman Khan accompanied her in the former while in the latter she performed alongside Aamir Khan, Aishwarya Rai, Akshaye Khanna and Rani Mukherjee. The following year, she was part of the judges panel at Femina Miss India. She made her theatre debut as the female lead in Feroz Khan's "All The Best" in February 2001. In 2002, Khanna opened her own interior design store in Crawford Market, Mumbai, called The White Window, in partnership with her longtime friend Gurlein Manchanda. Since then, the store has received the Elle Decor International Design Award. She has opened up another branch of the store elsewhere in Mumbai. She does not hold a professional degree and worked with an architect for two years to learn the procedures. During her pregnancy, she practised maps and designs using CAD. Khanna did the interiors for Rani Mukerji's, Reemma Sen's and Tabu's houses, Kareena Kapoor's Bandra flat in 2008 and Poonam Bajaj's design studio. On the request of one of her clients, she ordered a company to make a golden toilet seat. Khanna is the Indian brand ambassador for L'Oréal.