Lovato, 18, is currently seeking treatment in a medical centre for 'emotional and physical issues'.
Her co-star Martin said the actress is a 'good girl' and she added to Hollyscoop: 'I'm so proud of Demi. I know she is doing the right thing. I think it's awesome that she did it despite the press she may get.'
She added: 'She's a good girl and she will find her way back.'
Martin, also 18, said Lovato's situation has helped put her own life into perspective.
She said: 'Just watching my friends go through stuff like that is in itself a lesson. And the best way to learn the lesson.'