Demi Lovato hinted at bad blood between her and her former life coach after posting a cryptic message on her Twitter feed.

The 25-year-old recently revealed she had relapsed after being sober for six years, and seemingly confirmed she had parted ways with Mike Bayer, who is her former sober coach.

He previously appeared in her documentary, Simply Complicated, to talk about guiding her through her past battle with addiction.

Bayer shared a vlog on Instagram on Thursday (05Jul18), sharing with his followers his "biggest pet peeve" with celebrities, although he did not name the Sorry Not Sorry hitmaker.

“I’m here today to explain to you that being an artist and being talented are two different things. To me being an artist is living your authentic life. I believe everyone out there is an artist,” he said. “I think if somebody uses it as an excuse to be late, or insincere, or rude, or unapologetic, that’s not being an artist, that’s being a jerk. And you shouldn’t stand for that.”

One of Demi's fans commented on the Instagram post, and quipped: "Good luck on your blog", which the singer liked.

She then shared the same comment on Twitter, simply writing: "Good luck on your blog.

The former Disney Channel star also liked a comment from actress Ruby Rose’s comment on Twitter, which referenced the 'Burn Book' from Mean Girls and the film quote: “You let it out, honey. Write it in the book.”

Eagle-eyed fans of Demi's noticed that she unfollowed her former life coach from Instagram and Twitter in June.

The singer entered a treatment facility in 2011, where she was treated for bipolar disorder, bulimia, self-harm and addiction. She relapsed after she left the treatment center, then entered a sober living facility for a year.