Demi Lovato applauds Bebe Rexha.

The "Cool for the Summer" singer had a lot of love and respect for Rexha, 29, after she called out designers who allegedly refused to dress her for the Grammy Awards for being "too big."

"F---ing preach! Love this and you for speaking your mind and using your voice!!!" Lovato, 26 – who has previously spoken out about her body image issues -- wrote, leaving a handful of clapping emojis next to her comment. On Monday, the "In the Name of Love" songstress posted a video expressing her frustration with designers whom she claims deemed her size 6/8 figure too full to dress.

Bebe Rexha Slams Designers Who Say She's 'Too Big' to Dress for 2019 GRAMMYs 

"So I finally get nominated at the Grammys and it's like the coolest thing ever," Rexha said in an Instagram clip. "And a lot of times artists will go and talk to designers, and they’ll make them custom dresses to walk the red carpet. So I had my team hit out a lot of designers, and a lot of them do not want to dress me because I'm too big. Literally, like, I'm too big."

"If a size 6/8 is too big then I don't know what to tell you," she continued. "Then I don’t want to wear your f---ing dresses. Because that's crazy. You're saying that all the women in the world that are size 8 and up are not beautiful and they cannot wear your dresses."

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Since her post, celebrities like Tyra Banks and Sofia Carson have expressed their love and support.

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Designer Michael Costello also offered to dress the Grammy-nominated artist for the special night. "Bebe we have been friends for a long time i got you ! Call me @entertainmenttonight @beberexha I HAVE WHOLE GLAM TEAM FOR YOU INCLUDING @nealfarinah will do your hair. Let’s make Grammy moment history," he wrote on Instagram alongside ET's article.

Christian Siriano, known for dressing celebrities who have oftentimes encountered the same problems, also took to Twitter to respond to fans after they tagged him in Rexha's post. “Thanks everyone for the love! We have dressed @BebeRexha a few times and would love to do it again,” wrote the former "Project Runway" contestant.