The 18-year-old Hannah Montana star sparked outrage last week (10Dec10) after film footage of her smoking a huge pipe, allegedly containing the legal high Salvia, hit the web.
The video has led to Cyrus being slammed by anti-drugs groups, but Gilbert - who has battled alcoholism and substance abuse issues in the past - is adamant the star meant for fans to see the footage of her intoxicated.
She tells AOL News, "These days, everyone with a cellphone is a paparazzo. How high do you have to be to let a friend film you? I think she wanted to get caught."
And Gilbert has her own doubts about whether the substance in the bong was really Salvia.
She adds, "That's bulls**t! I think it was marijuana."