Justin Bieber, Selena Gomez Credit: Brian Babineau/WireImage.com; Michael Simon/startraksphoto.com

Singing through the heartache?

During a Boston concert on Saturday night, Justin Bieber summoned another world-famous Justin -- Timberlake -- in a potential nod to his fresh split with Selena Gomez.

Armed with just a guitar, with another band member strumming as well, the 18-year-old singer crooned a stripped-down, acoustic version of "Cry Me a River," Justin Timberlake's smash 2002 ballad inspired by his own split from Britney Spears.

The Canadian-born sensation left it vague when asked about the split with Gomez, 20, during a radio interview that same day." I don't know what to say," Bieber, 18, told Open House Party radio host John Garabedian. "I don't know what's going on in my life . . . To even assess that it doesn't make sense 'cause I have not made any comment."

(Multiple sources confirmed the split to Us Weekly Friday Nov. 9.) For her part, Gomez also had work to distract herself; on Sunday Nov. 11, she promoted her clothing line Dream Out Loud at a K-Mart in White Plains, just outside NYC, and had a bright smile for the cameras.

"Selena broke up with Justin about a week ago. It's been a really challenging experience over the last year because of their crazy schedules," an insider told Us. "Selena definitely had some major trust issues with Justin."