Demi Lovato Is Sorry (Not Sorry) After Knocking Out Jay Glazer's Tooth in a Boxing Session

Demi Lovato packs a strong punch, so strong that she just knocked out Jay Glazer's front tooth!

The singer posted a video this morning from her training in West Hollywood showing the aftermath. Lovato captioned the video, "Holy shit I literally knocked @jayglazer’s tooth out during training this morning - while he was wearing a mouth piece!!!! Hahahahaha sorry (not sorry) Jay!!!"

A makeup-free Lovato can be seen looking shocked and a little embarrassed when Glazer rang the bell to make the announcement ... with his tooth in hand.

She's been training at Glazer's Unbreakable Performance Gym for years and got back into it after she left rehab back in November.

As The Blast reported, Lovato has been very focused on her health and sobriety following her near-fatal overdose last year.

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