The 'Twilight Saga' star dated Joe Jonas soon after he split from the singer-and-actress and despite rumours claiming they were at war, Ashley says that couldn't be further from the truth.
Speaking about Demi – who earlier this year checked out of rehab after receiving treatment for personal issues – Ashley said: "I'm really happy that she's doing well.
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"She and I never had a problem with each other. But, you know, it doesn't go away.... Jen Aniston still gets asked about Angelina Jolie."
Ashley also spoke about the close friendship she has with her other 'Twilight' co-stars – including Robert Pattinson – as they've all helped each other cope with the pressures of being thrust into the limelight.
Speaking to the new issue of Allure magazine, she said of her co-stars: "Oh, Rob. He's very endearing, but you've seen his interviews. He's like, 'Ah, I don't know.... Oh, God.'
"All of us essentially were unknown. So everyone kind of went through this crazy whirlwind together. It was really nice to be able to confide in people who were going through the exact same thing."