Temasek Holdings, the Singapore government's investment arm, is acquiring 4.99% stake in Bharti Airtel, India's largest cellular telephony operator.Singapore Telecom is already a large shareholder in the company."Bharti Enterprises continues to maintain a controlling interest of over45% in Bharti Airtel through its subsidiary Bharti Telecom," said a statement issued by Bharti.One of Bharti's group companies has decided to grant an option to acquire an indirect stake in Bharti Airtel to a wholly-owned subsidiary of Temasek. The option arrangement envisages acquisition of shares which, on exercise, will result in a 4.99% stake in Bharti Airtel.