Nicole Richie will use her own drug addiction as a ''tool'' to warn her children.

The 36-year-old fashion designer - who was arrested in 2003 for possession of heroin, has been in rehab and was briefly jailed in 2007 for driving under the influence - is aware all her past problems are in the public eye and she will speak frankly with Harlow, nine, and Sparrow, eight, when they get older so they understand the pitfalls of substance abuse.

She said: ''My past is out there. I have no choice but to be honest.

''I mean, it is what it is. What I can do is use that experience as a tool for when my kids get older. They know that people have died from drugs because they go to school and it happens.

''Everything [about my past] is out there and I have no choice but to be honest with them. And you know what? That is very freeing to me.''

But Nicole - who has her kids with husband Joel Madden - will ''ease into'' the discussion with her children as they grow older and able to understand more.

She added in an interview with You magazine: ''We're going to ease into it later on down the line. We're starting with, 'Mummy got grounded a lot.' ''

And the former 'Simple Life' star - whose father is singer Lionel Richie - thinks going through her problems in the public eye was ''good'' because it forced her to confront her issues.

She explained: ''I think getting into trouble and going through everything in the public eye was good because if I had cleaned up without anyone knowing, maybe I would have figured out how to slip back into it.''

The 'Great News' actress has more than five million followers on Twitter, but she has no plans to allow her kids to use social media.

She said: ''Oh my God, they can't even go on Google.''