Mollywood actor Prithviraj celebrated his birthday on saturday at the sets of Santhosh-Sivan's Urumi. The flick has Prithvi and Genelia in the lead roles. The actor was received with birthday wishes from all his co stars. Though he thanked all his friends and well wishers for their greetings, he was all busy at the sets of Urumi, where the climax scene was shot. The climax scene according to the actor is the most massive ever in mollywood industry. “Over 100 horses, 150 stuntmen, over 1000 extras, explosives and multiple cameras”, the actor was quoted as describing the climax scene.