BENGALURU, Dec 24 (Reuters) - Indian shares advanced on Thursday on the back of gains in Reliance Industries and financial stocks, as news that a Brexit trade deal was close boosted investor sentiment ahead of the Christmas holiday. The NSE Nifty 50 index rose 0.64% to 13,688.60 by 0352 GMT and was set for its third straight day of gains, while the benchmark S&P BSE Sensex was up 0.63% at 46,742.16. Britain and the European Union were on the cusp of striking a narrow trade deal on Thursday, media reports said, boosting Asian equities. In Mumbai, shares of India’s most valuable company, Reliance Industries, gained nearly 1%. The Nifty’s banking, PSU Bank, and financial indexes rose between 0.8% and 1.5%. Shares of Bharti Airtel Ltd rose as much as 2.5% and were among the top three percentage gainers on the Nifty 50 index. The telecom operator added 3.67 million new customers in October, the highest among other telecom operators in the country, data showed on Wednesday. Bucking the trend, the Nifty IT index inched 0.3% lower after hitting record peaks in the previous two sessions. Biscuit maker Mrs Bectors Food Specialities is slated to make its market debut later on Thursday. (Reporting by Chandini Monnappa in Bengaluru; Editing by Aditya