I worked out at the referral-only studio that's a favorite of Hailey Baldwin Bieber and Kendall Jenner. It was an intimate experience and I loved it.

• I took a pilates class in a referral-only studio in LA next to a famous influencer.
• The experience was intimate and relaxed, and I really enjoyed my time there.

When I heard about Forma Pilates, the buzzy, celebrity-approved, and referral-only Pilates studio led by Liana Levi of "The Skinny Confidential" podcast, I was instantly intrigued.

With celebrity clientele like Hailey Baldwin Bieber and Kendall Jenner, as well as rumors of class prices going up to $500 for an hourlong private session, I knew I needed to know what the hype was about. After taking one class, I understand why everyone loves it.

The studio is big and beautiful

I booked a class with Levi at the studio's original location, the pool house of a gorgeous and very large home outside Westwood Village in Los Angeles. Upon arrival, I found no signage or indication of the highly talked-about studio. In fact, it took me knocking on the front door to even know I was in the right place.

Levi directed me to the backyard, and I made it up the stairs to the airy, clean studio with open windows that offered elevated views of the greenery, which made it feel more like a small tree house than a Pilates studio. The space has a small entrance with shelves for props and supplies, two reformers — often touted for their nearly $10,000 price tag — and a small space in between for Levi to instruct.

Class began, and it took me less than five minutes to realize it was going to be tough, really tough. I'm bouncing back from an injury, so I wouldn't consider myself in fighting shape, but I've been working with a personal trainer and doing strength training four times a week for the past three months. I've also done my fair share of mat Pilates classes, so I didn't anticipate struggling as much as I did.

The intimate setting allowed for the attention I needed as a newbie

Thankfully, Levi and my classmate, the TikTok celebrity and Forma Pilates regular Addison Rae, were incredibly encouraging and assured me the first time was tough for everyone.

We went through a flow of precise exercises that worked the entire body, starting with standing arm exercises using the reformer's vertical stand, then moving on to the carriage for variations of crunches and leg lifts that were so difficult, I was shocked I could — clumsily — complete them.

The two-person class offered the individual attention I desperately needed, with Levi adjusting my form and sometimes my entire movements throughout the class in a way that was helpful, not discouraging.

In true LA fashion, we chatted about zodiac signs and aura colors, and it became clear that Levi's ability to form personal relationships with her clients, in addition to the tough workouts, was a critical component of the studio's success.

Conversations came between sets, and Rae asked Levi who she'd still like to have in class. I was not surprised to hear her say Gisele Bündchen and Beyoncé, but I was surprised to hear that she enjoyed having athletes in the class.

When I talked to her later, she said her studio was less about being a tony hot spot to attract celebrities and more about creating a safe space and support system for people in the industry, adding that she's not looking for people to come in just once, take a photo in the selfie mirror, and leave — she wants people who desire to be a part of the community.

Despite all the stars that she's taught, she admitted she occasionally still got starstruck when teaching people she admires, like LeBron James.

I'm not sure if it was the amount of focus the workout required or the easy comfortable nature of the class, which felt a lot like hanging out with a small group of friends, but the class flew by. I was shocked and only a little relieved after I finished my final set.

While there are multiple Forma Pilates locations in Los Angeles and one in New York, it's still tough to get a referral for an in-person class, so Levi has created an online platform that allows anyone to try the Forma method with minimal equipment for $50 a month or $450 a year.