Kolkata, April 23 (IANS) Prime Minister Manmohan Singh received thunderous applause at a rally Saturday when he affectionately addressed Trinamool Congress chief Mamata Banerjee as "my sister".

 
 He made the remark at the start of his speech at a joint Congress-Trinamool election meeting at Dum Dum in North 24 Parganas district which was attended by thousands of supporters of both parties.
 
 The prime minister also clapped the loudest when Banerjee rose to address the crowd. He also called the railway minister a "valued partner" in the Congress-led United Progressive Alliance (UPA) government.