"Pete was with Nadine last weekend and picked her up from her home in Reading. She stayed with him until Monday when he went into rehab," the Daily Mail quoted a source, as saying.
Insiders claim that the couple had been seeing each other while Pete was with Kate and it was Nadine who convinced the rocker to go back to rehab, something that the supermodel failed to do.
"They do have a lot of history. They dated before Pete met Kate and have remained very close. He confides everything to Nadine and she always soothes him and makes him feel better," the source said.
"Pete was actually seeing her when he was going through a difficult phase with Kate in December. They spent the night together at a hotel," the source added.
The source said that Moss, who broke-up with Doherty recently after he cheated on her with a South African model, had banned the singer from seeing Nadine after learning about their close friendship.
"She will be devastated to hear he is back with Nadine. She always suspected something was going on between them, which is why she banned him from seeing her," the source said.