Demi Lovato's ex keeps her sober

The "Sorry not sorry" hitmaker, who completed her 90-day rehab treatment for drug overdose a few days ago, is still heavily dependent on her former beau Wilmer Valderrama, to remain sober.

A source close to Lovato told tmz.com that Lovato and Valderrama communicate regularly.

"She and Valderrama still communicate regularly. Valderrama was a crutch for Demi through her hospitalisation and visited her in rehab too. The two talk several times a week and meet up as well... but it's nothing romantic, simply a supportive friendship."

The singer recently left rehab stint, which followed her hospitalisation from an overdose in July.

She is now spending three days a week at a sober house, which has counselling staff on hand, as well as people who she can share experiences with.