Justin Rejects BRITNEY'S APOLOGY!

Oh, snap! Just days after Britney Spears praised his new track Selfish and apologized for "some of the things I wrote in my book," Justin Timberlake sent a message to his ex during one of his concerts, reportedly telling the crowd, "I'd like to take this opportunity to apologize to absolutely f-ing nobody."

Justin, 42, made the remark just before performing Cry Me a River, the 2002 breakup song he wrote about Britney in which he accused her of cheating on him. (The video for the song even featured a Britney look-alike.) Britney, 42, is devastated Justin didn't accept her mea culpa, a source tells In Touch.