ABS-CBN's and GMA's biggest stars came together to mark another milestone as they joined the debut of "It's Showtime" on GMA's second free-to-air channel, GTV today (July 1).

The premiere episode on GTV was also the grand finals of the first "Tawag ng Tanghalan Duets," wherein Marielle Montellano and JM Dela Cerna won as the grand champions.

They garnered a total average score of 98.3% from the combined hurado scores from judges Louie Ocampo, Zsa Zsa Padilla, Nyoy Volante, Marco Sison, Erik Santos, Gary Valenciano, Jona, and Darren Espanto plus Kapuso singers Christian Bautista and Mark Bautista. They beat John Saga and Kim Nemenzo with 95.3% and Eumee Capili and Anton Antenorcruz with 91.6%. As the first "TNT Duets" champion, JM and Marielle received P500,000 and a trophy designed by Toym Imao.