Tomorrow night's (April 30) episode of 'The Voice' marks the semi-finals and the coaches are going all out. Team Christina and Team Blake will pair up to perform Lady Gaga's 'Edge of Glory,' according to NBC, which airs the show. Since each team has two members, it'll be four of them partnering up to rock Gaga's majestic anthem.

We're certainly excited about seeing Team Blake's Erin Willett belt out the song, as well as seeing what opera "mann" Chris Mann does with the tune, as well. But it does make us think back to some of the not-so-nice comments that Xtina made about Gaga when she embarked on her press tour and media blitz for her album 'Bionic,' which was a flop that failed to yield any hits.

Xtina strayed from her signature style – her big, booming voice -- in favor of a more processed, synthy sound. It backfired. But during the promo run, she took to dissing Gaga, whose star was on the rise at that point. She said she wasn't sure "who that person is" or if she was a man or a woman. Ouch.

Given Xtina's recent snub of Justin Bieber (which she denied) and the Wanted's less-than-warm-and-fuzzy encounter with her, it seems like she might be a bit prickly, no? Still, we're sure she's a pro who will guide her team through Gaga's song with grace and poise.