The former couple - who dated for two years until 2007 - were spotted dining together at Patys restaurant in Toluca Lake, California on Monday (25.03.13).
But a source told HollywoodLife.com that the 20-year-old 'Can't Be Tamed' singer, who is still working through ''serious problems'' with her fiance Liam Hemsworth, was simply having a business meeting with her former love interest.
The insider said: ''[There was] absolutely no romantic vibe at all, at any time while they ate and while they were there. It seemed more like a meeting than a friendly chit chat or get together -- it was a more serious tone, based on their demeanour. They seemed to be having a business meeting -- they were on their phones and then they left without incident.''
Another source said: ''They left separately. Liam was fully aware that she was out with him, there is nothing to worry about at all.''
Miley and Australian actor Liam, 23, took a break from one another earlier this month amid reports the actor cheated on her with January Jones and he was tired of the singer's partying lifestyle.
But a source recently said the couple - who got engaged last summer after meeting in 2009 on the set of 'The Last Song' - ''genuinely love each other'' and will look to get over their recent troubles.
The insider said: ''There are some serious problems going on, but seeing them together, they do genuinely love each other and they really do want to work it out.''