Keegan-Michael Key on how a friend (and helium) inspired his 'Super Mario Bros.' Toad voice

Though Mario is undoubtedly the star of The Super Mario Bros. Movie alongside his partner and sibling Luigi, there are plenty of other characters in the vibrant, Nintendo-inspired world to be on the lookout for. One of them is Toad, voiced by Keegan-Michael Key, who brought an interesting technique to bringing his character to life.

Speaking to Universal Pictures publicity at the Super Mario press junket, Key -- best-known as one half of the comedy duo Key & Peele and for films like Keanu and the streaming series Schmigadoon! -- described his version of Toad as a "gung-ho" devotee of all things Mushroom Kingdom, ready to defend his realm with everything he's got, and always ready for an adventure.

RELATED: Anya Taylor-Joy on reimagining Princess Peach for The Super Mario Bros. Movie

"He absolutely, positively loves where he's from, and when he encounters Mario, he wants to show Mario everything about this wonderful place where he lives," Key said.

That enthusiasm, of course, had to come through for the character in Key's voice, which is completely transformed from his regular speaking voice and, he believes, any other voiceover role he's taken on so far in his career.

"I've done several animated films where I've done voiceover, and this one is really special because I had the opportunity to really do a voice that's so completely different from my voice," he said. "You will not be able to recognize it's me in this movie, and that to me is a proud accomplishment."

So, why did Key's voice differ so much this time around? It started with borrowing the speaking rhythms of a close friend and applying that to Toad's dialogue. Then, when he got in front of directors Aaron Horvath and Michael Jelenic, he got a request to tweak the pitch.

"I was using my friend as the model, and then when I got to the director, I was using my voice as you hear it now, and the director's like, 'I like what you're doing, but can you get it a little bit higher?'" Key recalled. 

So he went higher, and then higher still, and then higher still, until he finally had to rely on some very specific visualization to keep himself at the right level for Toad's excitable sound.

"We got it up there, and I started thinking about 'Keegan, just pretend you're on helium, just pretend you're on helium the whole time,'" he said. "And then I would just imagine myself sucking on a helium balloon so I could get to the voice."

From what little we've heard from the character so far, the voice Key landed on is both very different from his own speaking voice, and a perfect fit for Toad's look and overall vibe.

We'll hear more when The Super Mario Bros. Movie hits theaters Apr. 5. Order tickets right here!