The fourth season of the American realitytalent showThe Voice premiered on March 25, 2013 on NBC and was hosted by Carson Daly, while Christina Milian returned as the social media correspondent. Coaches Adam Levine, CeeLo Green, Christina Aguilera and Blake Shelton returned, though Green and Aguilera appeared as performers instead of coaches. Shakira and Usher then served as replacements coaches for Aguilera and Green. The team sizes were trimmed back down to 12 per team (season two's team size), with each coach having two 'steals' in the Battle Rounds.