Richie 'grieving over DJ AM's death'

Friends have reportedly revealed that Nicole Richie is finding it hard to deal with Adam 'DJ AM' Goldstein's death.

The socialite was engaged to Goldstein in 2005 and the pair remained friends after they split.

Star magazine quotes a source as saying: "Nicole almost collapsed in grief when she found out. She said she felt like her heart stopped for a few minutes. She's horrified and regrets that she didn’t reach out and help him."

Goldstein, who was found dead last week after a suspected drug overdose, allegedly helped Richie battle her own drug addiction.

The 36-year-old was buried in a private memorial today.