Christina Aguilera dissed superstar Justin Bieber during his appearance on "The Voice" Tuesday evening.
After the 19-year-old "Boyfriend" singer was introduced to the audience he jumped off stage to greet the four "Voice" coaches including Adam Levine, Cee Lo Green, Blake Shelton, and Aguilera.
It was then that Bieber had an awkward exchange with 31-year-old Aguilera, who held out her hand for a shake while Bieber went toward her with an embrace. As Bieber made his way toward Shelton, Aguilera's smile faded into a cold and glowering look.
Twitter was flooded with people's reactions of the cold exchange between the singers.
"Famously pleasant human being Christina Aguilera's expression post-hugging Justin Bieber has made my day," posted John.
Kerri wrote, "And that was Christina Aguilera overtly hating on Justin Bieber. #The Voice."
"Did anyone just catch how fake Christina Aguilera just said hi to Justin Bieber on the voice," posted Sugar. "She must [not] like him."
On Wednesday, Hollywood Life wrote, "Christina Aguilera was so rude to Justin Bieber on #TheVoice last night!"
Perhaps to amend her cold reaction, Aguilera's spoke warmly about Bieber after Tuesday's episode of "The Voice."
"You know, he's definitely popular with the ladies and he came on the show tonight, it was a fun burst of energy," the vocal coach told Us Weekly. "He's a really charismatic guy and it was cute!"
While appearing on the reality television show, Bieber delivered exciting news to his thousands of fans. The singer debuted the music video for his new single "Boyfriend."
His new album, "Believe," will be in stores June 19.
Bieber will return to "The Voice" during the show's finale on May 8. The singer has over 20 million followers on Twitter, and his single "Boyfriend" remains a top-selling song on iTunes.
Ahead of his new album's release, Bieber has kept his fans updated on the progress of "Believe." On Wednesday, the singer posted to the micro blogging site: "just finished cutting one of the most important records of my life. an amazing and strange feeling at the same time. #HONORED"