The 'Slide Away' singer reconnected with her friend on the first episode of her 'Bright Minded: Live WIth Miley' Instagram Live series - which will see her chatting to a different star each day - and she opened up to Demi about her feelings after performing alongside Robin Thicke in a tan bodysuit at the MTV Video Music Awards in 2013.
She said: "I basically went through two or three years where I wouldn't wear shorts. I stopped wearing skirts on stage, all this s**t because after the VMAs and I had on my cute little nude bodysuit, everyone started comparing me to a turkey and putting a turkey in my outfit.
"I was just so skinny and so pasty and they kept putting me next to this turkey, and I was feeling so bad on myself that I did not wear a bikini for like two years and no one thought that that would ever made me feel some type of way...
"I think what was so hard about it was my brand has always been about being so unapologetically myself and being confident, and the worse thing that I would feel like I would be to my fans is lying or a fraud."
Demi, 27, was sympathetic, as the 'Sober' hitmaker revealed she and Miley, also 27, go through periods of being "closer and then distance".
She added: "First of all, I'm so sad that you went through that and I had no idea.
"I wish I could've been there, but I didn't know and I feel like we've gone through like times where we're closer and then distant -- and that's fine, that's what friends do.
"I just wish I could've been there for you. But if that ever f***ing happens again, you better call me."
Meanwhile, Miley agreed that sometimes "life is moving so fast", but they will always be there for each other when they need the support.
She explained: "We can not talk forever and then some bulls*** will go down, and I'll just know you're the person I want to reach out to.
"In dark times, it's really important to reach towards those who are illuminated. I just think that you're such a light -- even if it took this crisis to get us connected again."
