Many fans may be excited over news that Christina Aguilera is returning to "The Voice."

However, this news doesn't sit well with one particular person - Gwen Stefani, who will be leaving the reality talent search to make way for the "Candyman" singer.

"Everyone knows Christina thinks this is her show and she can swan in and out whenever she likes. She refers to Gwen as 'the substitute!'" a source told OK! Magazine, as quoted by Celeb Dirty Laundry.

Though Gwen Stefani allegedly heard about Christina Aguilera's "the substitute" diss, the No Doubt singer doesn't seem to resort to name calling. Instead, Gwen purportedly intends to fight back by being the best female mentor "The Voice" has ever had.

"She knows Christina turns her nose up at her and she's been told about the 'substitute' jibe - and she has a few tricks up her sleeve herself," the source continued.

"She plans on going out as THE only coach everyone wants back - the most memorable coach and 'face' of the show."

Aside from Gwen Stefani, a lot of "The Voice" staff members are allegedly not too happy about the news that Christina Aguilera will be occupying one of the coaches' chair on the upcoming season.

There have been previous reports that "The Voice" staff and crew are not very fond of Christina Aguilera, and would purportedly prefer Gwen Stefani any day - the No Doubt vocalist is allegedly a lot easier to work with than the "I Turn To You" singer.

"She was really difficult to work with this season. Tensions between her and Adam were consistent, but she also just had a really bad attitude," a source close to "The Voice" production told Radar, as quoted in a previous news report.

"She showed up late a lot, took forever for hair and makeup and was just very demanding."