This article originally appeared on People.com. 

When it comes to telling the truth about health, trainer and fitness entrepreneur Tracy Anderson doesn’t have much faith in Hollywood. But there are a few celebrities she does have faith in, and one of them is Lena Dunham.

“That’s what I love about her — because she speaks straight and speaks her mind and she puts it out there,” Anderson told PEOPLE at the Breast Cancer Research Foundation’s Hot Pink Party in New York City on Friday. “She’s telling the truth, and no one tells the truth.”

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Anderson is referring to the reason behind Dunham’s recent interest in fitness. “She had significant health issues,” Anderson confirmed, referencing the actress’ struggles with endometriosis and OCD. “She was open and transparent about her health issues, but our convoluted f-ed up celebrity culture was like, ‘What diet is Lena doing? Lena lost weight,’ and Lena was like, ‘I was freaking sick!’ Like, it’s just crazy,” Anderson said. “And by the way, I think she’s making that statement.”

Dunham kicked up her fitness in the last few years, after she learned that working out helps her manage her anxiety, and started doing yoga and taking classes with Tracy Anderson.

“She didn’t come to me to make her body look different, she came to me to feel better,” Anderson explained. “And I think that she’s our most important influencer of our time. She came to me and when she was so vocal about how my program helped her with her OCD … for me, when people come to me from the vanity thread, I know that they have a lot of balance work to do in their bodies. So when somebody comes to me with, ‘My health matters first, I just want to feel good in my skin, I want to be healthy,’ that’s where it needs to come from. Because there’s not one specific definition of beauty and we really have to move the needle in the other direction for that.”

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Anderson, who also recently wrote a book aimed at teens, thinks that “someone like Lena, who is beautiful and articulate and smart and heartful, she’s someone that can help us do that. And I think she’s doing it, a damn good job of it.”

In honor of Dunham’s 31st birthday on Saturday, Anderson shared her love for the writer and actress on Instagram. “Happy Birthday to the most important influencer of our time!!! Trust me ladies in 10 years you will not have enough ways to say thank you in your vocabulary for the roadblocks this incredible woman will have unblocked for us. I stand beside you in all of your efforts my darling! I hope you relax your advocating voice today and @jackantonoff makes you pancakes in bed! Love you forever and always! ”

Dunham isn’t the only celebrity Anderson admires. She has a soft spot for Jennifer Lopez, which is why she trained her last week even though she isn’t technically available for hire for personal training anymore. And of course, she loves Gwyneth Paltrow, who is her business partner. But Anderson explains that the reason she admires the two stars and continues to work with them because of the way they approach fitness.

“My biggest complaint [when training celebrities] was always, they needed to be more like Jennifer Lopez, where it’s like, ‘No no no, I work out always, I’m smart about how I work out. I want to be comfortable and healthy in my own skin.’ And it’s not this, ‘Can you please get me ready for this sex scene I have to do in two weeks?’ or ‘I have to shoot a video in two weeks…’ and I’m just like, that’s not the mentality,” she said. Anderson revealed that it is extremely common for celebrities to contact her for reasons like that — 911s, as she calls them. “And then to see those kinds of people go out and be on the cover of a wellness magazine, especially as much as I know about them, I’m like, ‘Oh gosh, wow, that’s shocking.’ ”

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So Anderson put her foot down. “I don’t work with the 911. I’ll work with the 911 if the 911 comes in and is like, ‘I’m committing to…’ that’s how Gwyneth and I started,” she recalled. “Gwyneth was like, ‘I have a 911, I can’t get my baby weight off after Moses, I’ve gotta film something.’ But she was like, ‘I will do everything that you say and I am in it, and I am a really good student.’ And she was willing to take all the steps to really actually invest in what I do,” Anderson said.