Britney Spears opened up about feeling "triggered" by Justin Timberlake's mockery of her public apology following their breakup years ago.

The exclusive source shared with US Weekly that the Toxic singer was still emotionally hit by the unpleasant remark made by her former partner Justin Timberlake about their past relationship struggles.

While performing on the song Cry Me a River at New York City’s Irving Plaza, the Selfish singer announced, “I’d like to take this opportunity to apologise to absolutely f–king nobody.”

The insider shared “Britney was annoyed after his onstage statement.”

Timberlake, 43, remarked came shortly after the Circus crooner posted an apology on January 28 for “some of the things” she wrote in her memoir The Woman In Me.

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She wrote in her apology, “If I offended any of the people I genuinely care about I am deeply sorry.”

The source also added that Spears and Timberlake “seemed [like] they were both moving forward,” during this time, “but when he made fun of her apology it triggered her.”

The Womanizer songstress’ close circle is also not happy with the Trolls star's comment as the source said, “Those close to her wish Justin was more of a stand-up guy and would have just moved on because what he did really hinders her recovery.”

Timberlake comments related to her were agonising and a source shared that Spears’ “turning point for her mental issues started when [Timberlake] broke up with her so many years ago.”