But soon, designer Christian Siriano came to the rescue for her Ghostbusters premiere look!
After discussing options together, they came up with this glorious creation, and boy, would those other designers be envious now...
She accessorised the look with a stunning Dannijo necklace.
Leslie told E! News on the red carpet: "It takes a real designer to design for real women. That's what I was saying. I'll always say that."
She also recently explained her frustration during a Facebook Live chat with E! News.
"I've been six feet tall since the sixth grade," she said. "It was always hard for me to find clothes. So for the industry not to make clothes for me, the average woman that actually goes into the store and buys them, yeah, it kinda pisses me off a little bit. And I'm not saying that there's nothing wrong with being curvy, 'cause I'm a size, like, 10. I mean, I used to be a 14."
And she wasn't the only one who looked incredible - her co-stars looked like a real team in beautiful multi-coloured creations: