"I believe in her 110 percent, but she needs to call [me]," the pop star, 30, told PEOPLE Thursday at the Hysteric Glamour VIP preview party. "If her publicist or somebody can get in touch with me, I just want to sit down with her and have it out."
Asked what he'd offer to Spears, McLean says, "First I would say, 'What the hell is wrong with you?' Second I would say, 'What is really wrong with you? What are you not saying to everybody else?' "
McLean, a recovering alcoholic who also happened to rise to fame around the same time as Spears, says he thinks he knows part of what the 26-year-old star is going through.
"She has given people hints of her troubles, but fear is a really big thing, and depression. ... I've been through it. I'm coming up on six years sober," he said at the party hosted by Tracey Ross at her Sunsent Plaza store in West Hollywood. "I just want to sit her down and pick her brain."
'Do You Want to Die?'Ultimately, McLean says he believes the troubled singer wants to – and can – get her life back in order. " [I want to be] just someone who can tell her straight. I'll say, 'Hey, do you want to die? Is that what you want?' If that is what she really wanted, she would have done it already. I know that is not what she wants," he says.
McLean also said Spears's pregnant 16-year-old sister Jamie Lynn has had a rough go but will be okay.
"You look at Jamie Lynn now and it is like, of course, she has no one to look up to," McLean says. "But I think she has a chance. Everyone has a chance to turn it around."