Gomez takes shot at Bieber on 'Letterman'   Play video

Justin Bieber became the butt of jokes during his ex-girlfriend Selena Gomez's appearance on a late-night TV show on Monday when she laughed about making the pop star cry over their broken romance.

The singer/actress allegedly dumped Bieber in November, but they reunited at Christmas for a skiing trip to Utah before splitting for good at the end of the year.

The former sweethearts have sent messages to each other through music ever since, with the teen heart throb releasing new song Nothing Like Us about his heartache, and Gomez performing a cover of Justin Timberlake's break-up anthem Cry Me a River in January, which she directed at her ex.

Now the 20 year old has caused Bieber even further humiliation with her appearance on The Late Show with David Letterman on Monday night, when she confirmed she was single and insinuated it was her decision to call time on the relationship.

When asked whether the couple was still dating, Gomez responded, "No, I'm single... I'm so good."

The host continued to press the issue, but the pretty Who Says singer made it clear the former couple had split.

Letterman, who chastised the teen for having too many tattoos during an interview last June, said, "Now, the last time he was on, he and I got into a conversation, and I - he said something and then I said something, and then he said something and I said something, and I made him cry."

And Gomez joked, "Well, then that makes two of us."

The snide remark left Letterman chuckling, and it's sure to kick Bieber while he's down - earlier this month the star was hospitalised after collapsing onstage due to exhaustion, embroiled in a nasty argument with a photographer, and accused of being kicked out of his French hotel for bad behaviour. He also upset British fans when he showed up late for a concert in London.