Kristen Johnston paid tribute to her sister Julie after she lost her battle with addiction Monday.

Johnston shared a snap of the pair on Twitter, saying: “She had the best belly laugh in the world.”

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The actress, who has also been diagnosed with lupus myelitis, a rare form of lupus that affects the spinal cord, has been open about her own past drug and alcohol addictions, writing about her struggles in her 2012 memoir Guts: The Endless Follies and Tiny Triumphs of a Giant Disaster.

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Johnston told Entertainment Weekly at the time, “The most important thing I want to express to people is that I’m not cured. I could probably relapse in a minute. Who knows?

“It’s just a weird disease that sneaks up on you and all of a sudden you’re boozing at the bar, or whatever. And it doesn’t have to be because of you or pressure or this or that. It just can be.”

She added: “The most important thing is that I didn’t want to set myself up for failure and be like, ‘Look at me!’ I wanted to write the book that I needed when I was suffering.”