Gwyneth Paltrow's Amazing Bod Is Partially Thanks to Beyoncé—and More Stars' Workout Playlists Revealed!

"I played some house music for Gwyneth one Friday and she wasn't feelin' it and was like, ‘Let's get some Beyoncé up in here!'" celeb trainer Tracy Anderson tells E! News

It's common knowledge that music is a huge part of a successful workout—low battery on your phone? Nope, can't do it. Forgot your headphones? Whoops, guess the gym isn't happening.

But when you find the right playlist to get your sweat on to, it's like a match made in heaven! Celeb trainer Tracy Anderson knows all about that, and has decided to combine her love for Beats by Dre and great workout music to create a #BeatsHourofPower playlist.

"You can't have a good workout without good music," Anderson told her class in Brentwood, Calif., last night before blasting her new mix. So what does a client like Gwyneth Paltrow, who has trained with Anderson for years, listen to when she's gettin' down in the gym?

"Anything Beyoncé!" Tracy tells E! News. (OMG, Gwyneth is just like us!)  Anderson adds that she tried to introduce different music to the GOOP founder, but she wasn't having it.

"I played some house music for Gwyneth one Friday and she wasn't feelin' it and was like, ‘Let's get some Beyoncé up in here!' Music is such a big part of my workouts, you've really got to feel the music and get into it. If you don't love the song you're not going to work your hardest."

Tracy continues, "We're seriously thinking of only playing Beyoncé on Fridays! Gwyneth was like 'Yeah, love it! Beyoncé Fridays!'"

The famous fitness trainer also tells us that Girls star Lena Dunham has started working out with her. "Lena loves it! She's not doing it to lose weight, she's doing it because it makes her feel good! We have so much fun working out together."

So what's on Dunham's playlist? "Lena really digs my playlists filled with Bleachers [boyfriend Jack Antonoff's side project]," Tracy tells us, and also mentions that there's one cutie that helps Jennifer Lopez get her heartrate up at the gym. "JLo and I have played Nick Jonas ‘Jealous' on repeat," she says and also mentions, "My A-plus students really have learned what it means to really get into the music."