The 35-year-old actor portrays Titania in the new Marvel TV series, a social media influencer who possesses super-human strength.
To prepare for the role, Jamil went all in on the stunt training by learning jiu jitsu, kung fu and combat in the air.
And while it's paid off for her character, the strenuous preparation didn't come without its consequences.
"I was hurting in place that I really didn't know exists," she explained.
"Like, you'll probably have to bleep this out, but I pulled a muscle in my a******. I didn't know that was possible."
Neither did we.
Jamil added: "I don't know how much of it ever gets to make it to the big screen because CGI is bonkers.
"But I got to do all my stunts pretty much myself. And that was something I've never done before because I'm the ultimate couch potato. I am just a puddle with bangs."
The star also elaborated on why she hopes people will 'love to hate' her character in the show, saying Titania's just 'so annoying'.
"She's just the messiest b**** in the MCU and I love that about her," she said.
"She's just very insecure, and that's where all of her badness comes from, is her deep need for love and attention."
Tatiana is the rival to our lead character Jennifer Walters, who transforms into She-Hulk and is portrayed by actor Tatiana Maslany.
Alongside Maslany, Jamil got to film with Mark Ruffalo as the OG Hulk in the upcoming show, an experience she described as 'incredible'.
She continued: "There was a day where we were all rehearsing together for a scene and he made it feel like we were just rehearsing for a school play - it felt so fun, so free.
"He's so generous, he's so playful, he's so not what you would think someone at that level would be. He's just a gentleman."
Joining Jamil, Maslany and Ruffalo in the series will be Tim Roth, who plays Emil Blonsky/the Abomination, Benedict Wong as Wong and Ginger Gonzaga as Walters' best friend.
She-Hulk: Attorney At Law will start streaming on Disney+ from tomorrow (17 August).
Featured Image Credit: Reuters/Alamy Stock Photo/Disney+