Her big sister, Rumer Willis, quickly regrammed the post and added, "So proud of my baby Buusk."
Tallulah giddily celebrated her one-year anniversary last year with a "celebratory jig.""Friends, lovers, family, various amphibians of undetermined origin, im real excited to say I have been a fierce sober warrior for 365 days as of today," she captioned an Instagram in 2015, where she does, in fact, appear to be dancing. "Thank you to the beautiful humans in my life who have helped me get here."
Her middle sister, Scout, friend Harold Kuhn, and stylist Maeve Reilly even helped throw her a "sober birthday party," which included a birthday cake, dragons, parasols, hand fans, and lanterns. "I am so wholly overwhelmed with love right now I want to cry," she wrote.
Tallulah has battled body dysmorphic disorder and depression. She entered a treatment center for 45 days in 2014, at the urging of her parents, and has been very open about her recovery on social media.
During an interview with Teen Vogue last year, Tallulah cited online bullying as a big factor of her low self-esteem and subsequent substance abuse and body issues.
"I was in a New York hotel room when I was 13… looking at a photo of myself online. I broke down in tears as I started to read the comments," she told the magazine. "I thought, I am a hideous, disgusting-looking person. I might be nice and I might be kind, but I'm a really unattractive human being."
"It wasn't about the anonymous cyberbullies -- I became my own worst critic," she added, noting that her depression hit its lowest point during college.