Appearing on The Tonight Show with Jimmy Fallon, Cara Delevingne showed off a party trick which stopped not just the audience in its tracks but social media.

The star of Amazon’s Carnival Row showcased how she can play Lynyrd Skynyrd‘s Sweet Home Alabama on an electric guitar … that she’s holding behind her head.

Delevingne in a Mariel Haenn corset dress in Manhattan on September 3. Photo: Getty

Yes, it’s a useless skill. Yes, it’s totally awesome.

And her party trick isn’t just limited to one song or one position, Delevingne (who also said she ate a rat for Bear Grylls and slipped effortlessly into the Irish accent she uses in Carnival Row) told Fallon.

She said she can play the guitar behind her back and “with my toes.” That particular claim wasn’t tested on the US TV show.

Delevingne also plays drums the conventional way.

As to how the model, singer and actress, 27, came to unearth the hidden talent, she said she likes to learn how to do things “the way other people don’t” and “unconventionally.”

She also admitted she enjoys “showing off.”

When Fallon handed her a guitar, Delevingne didn’t hesitate to tuck it behind her head and pluck out the famous opening riff of Sweet Home Alabama.

It’s not the first time Delevingne, who has been dating Pretty Little Liars star Ashley Benson for a year, has knocked Fallon and his viewers sideways with her party tricks.

Four years ago, she showed him her freestyle beat box chops. The clip has now been viewed 15 million times.

Then there was the time she threw down a heated rap battle with Superbad’s Dave Franco on ‘Drop the Mic’ on the Late, Late Show with James Corden.

Vanity Fair decided the guitar thing makes Delevingne a rare quadruple threat the likes of which not even Hugh Jackman or Seth McFarlane can compete with.

The celebrity site suggested now that her Carnival Row co-star Orlando Bloom is engaged to singer Katy Perry, there could be “some kind of collaboration” or a musical episode in the fairy fantasy’s second season, which was commissioned days after the first one debuted.

“Delevingne could play Teenage Dream with her toes while Perry sings with her hands? Anything is possible.”

For now, the star – snapped giggling in May as she and Benson, 29, carried a $650 bondage bench into their Hollywood home – may be too busy with Carnival Row.

From the first time she read the script, she was “intrigued” by her fairy character, Vignette, she told Collider, calling the Victorian-era set “just unlike thing else that I’ll ever experience in my whole life.”

The star leaves her London hotel on August 29. Photo: Getty

She said when she saw the show on a big screen at Comic Con, “I was crying because I was like, ‘Oh, my God, it’s so pretty.’

Delevingne called Vignette “much stronger” than she is, “but she’s also so compassionate and forgiving,” she said.

“I’m not like that. If someone hurts me, I’ll be like, ‘Bye, see you f—-n’ later!’ She’s like, ‘He loves me and he made a mistake.’

“She’s a bigger person than I am, I’ll tell you that. She has no pride, whereas I do. If someone hurts me, I’m like, “You made me look like an idiot. Screw you!” She doesn’t care about looking like an idiot or not.”

She said when she first tried her prosthetic wings on she was naked, and “I took so many pictures … because it just looks so crazy.

“They’re like big raw bits of bacon on you. That’s what it feels like.”