Once Upon a Time sneak peek: Emma protests Regina going undercover  

When Regina (Lana Parrilla) goes undercover to infiltrate the Queens of Darkness on Sunday’s episode of

, a surprising ally will try to convince her against it: Emma (Jennifer Morrison).

Fortunately, by that time, Regina has already learned that Maleficent (Kristen Bauer van Straten) & Co. are after the Author, and are planning to use Regina to steal a piece of information that could help them locate him. How will Emma react? Find out in our exclusive sneak peek.

James Bay adds some tambourine to Rihanna, Kanye West\'s \'FourFiveSeconds\'

Kelela and Arca team up for the gorgeous future-R&B track \'A Message\'

Modest Mouse share \'Of Course We Know,\' announce tour dates

Comedian Matt Braunger on pilot season, his new album \'Big Dumb Animal,\' and the science of titles

Netflix nabs Cary Fukunaga\'s \'Beasts of No Nation\'

Elizabeth Henstridge talks \'Agents of SHIELD\'...while playing \'Mario Kart\'

\'Dancing With the Stars\' portraits: 12 snap judgments