LOS ANGELES (Reuters) - NBC's singing contest "The Voice" got its second season off to a supersize start, attracting 37.6 million viewers on Sunday -- more than double the show's biggest audience last year, NBC said on Monday.

Enjoying a bump from the record 111.3 million TV audience for Sunday's NFL Super Bowl -- the most watched show in U.S. television history -- "The Voice" was the top entertainment show for NBC since the finale of comedy "Friends" in May 2004, when 52.5 million Americans people tuned in.

The bumper numbers bode well for "The Voice", which became a surprise and much-needed hit last summer for NBC, which has struggled for years to climb off its bottom place among the four major U.S. TV networks.

The show, whose judge-mentors include Christina Aguilera, Cee Lo Green, Blake Shelton and Adam Levine, will be shown in its regular slot on Monday in what is expected to be a popularity contest with ageing Fox ratings juggernaut "American Idol" on Wednesdays and Thursdays.

NBC said the audience for Sunday's second season premiere was up 161 percent from "The Voice"s previous biggest audience of 14.4 million in May 2011.

The figures were bigger than both the post Superbowl audiences for Fox musical comedy "Glee" and CBS reality show "Undercover Boss" in 2011 and 2010.

NBC is hoping that the popularity of "The Voice" will also get the network's heavily-promoted new musical drama series "Smash" off to a good start when it has its premiere on Monday night.