The 26-year-old singer recently left rehab after a 90-day stint - which followed her hospitalisation from an overdose in July - and is 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.
But it's believed to be her regular chats with the 38-year-old actor that are helping her the most, with a source insisting they are just good friends.
An insider told TMZ: ''She and Wilmer still communicate regularly. Valderrama was a crutch for Demi through her hospitalization 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 gossip site recently claimed the 'Confident' singer is keen to resume a normal life so spends the rest of her time at a private home and is free to visit the gym or run errands, though she has a sober coach with her around the clock.
The 'Sorry Not Sorry' hitmaker has also been attending regular Alcoholics Anonymous (AA) meetings.
Earlier this week, Demi was pictured catching up with Henry Levy - who she met on a previous stint in rehab - and pals think the clothing designer is a ''perfect sober friend'' for her.
A source said: ''Henry and Demi met a few years ago in rehab. They hit it off immediately and became fast friends.
''Henry takes his sober life very seriously and, when Demi sadly relapsed, they lost touch for some time... Henry is exactly the friend Demi needs right now.
''He is a perfect sober friend for her. Her friends feel he is a positive influence on her.
''Henry and Demi have been hanging at Demi's home watching movies. This is such a key time in Demi's sober process and just staying away from the party scene truly helps.''
The 'Sober' singer has vowed to ''dedicate herself'' to a life of sobriety following several years of struggling with addiction, and is thought to be distancing herself from her old friendship group, with the exception of Wilmer.
A source added: ''[She] has dedicated herself to her sober life and has surrounded herself with people in her programme.
''She is avoiding those in her social circle that supported her precarious lifestyle. Demi deserves a partner who will help her continue to live a clean life and her family and friends feel she is choosing more appropriate friends.''
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