Demi Lovato knocked out her trainer's tooth while boxing.

The 26-year-old singer took to Instagram on Tuesday (05.03.19) to share a clip from her gym in which her trainer holds up his missing tooth and exclaims that the 'Sorry Not Sorry' hitmaker ''knocked [his] tooth out'', even when he was wearing a mouth guard to protect against such injuries.

Demi captioned the video: ''Holy s**t I literally knocked @jayglazer's tooth out during training this morning - while he was wearing a mouth piece!!!! Hahahahaha sorry (not sorry) Jay!!! So coach, when's my first fight?! #unbreakableperformance (sic)''

Although the injury sounds quite serious, both Demi and her trainer seemed happy in the clip.

The gym video comes after it was recently claimed Demi is ''committed'' to her sobriety, after she was hospitalised for an apparent overdose eight months ago.

A source insisted the 'Solo' hitmaker has been working hard behind the scenes to remain sober and has cut off her ''enabling'' friends, with her biggest motivation being the chance to get back on stage.

Back in December, the singer admitted she is ''sober and grateful to be alive'' following her overdose.

She wrote on social media: ''If I feel like the world needs to know something, I will tell them MYSELF. Otherwise people stop writing about my recovery, because it's no one's business but mine. I am sober and grateful to be alive and taking care of ME. Someday I'll tell the world what exactly happened, why it happened and what my life is like today.. but until I'm ready to share that with people please stop prying and making up s**t that you know nothing about. I still need space and time to heal..

''I would love to set the record straight on all the rumours out there but I literally don't owe anyone anything so I'm not going to. All my fans need to know is I'm working hard on myself, I'm happy and clean and I'm SO grateful for their support. I'm so blessed I get to take this time to be with family, relax, work on my mind, body and soul and come back when I'm ready. I have my fans to thank for that. I'm so grateful, truly. I love you guys so f***ing much thank you (sic).''