McConaughey's Calm cameo is part of a new star-studded feature called "Sleep Stories".
With about 120 different Sleep Stories to choose from, subscribers can fall asleep to celebrities around the world: From the deep, dulcet tones of McConaughey or singer Leona Lewis, to the British twang of Stephen Fry or Little Britain's David Walliams.
But now, back to the most important player of all:
The How to Lose a Guy in 10 Days star recorded a 35-minute Sleep Story called Wonder, in which he shares the tale of a grandfather who explains the magic of the universe, and life itself, to his granddaughter.
McConaughey's voice, dripping in Southern charm, could put a hopped up racehorse to sleep.
"Well, hello there," he begins, dryly.
"I'm Matthew McConaughey and tonight, I'll be reading a special sleep story."
Oh, yes, you will be.
His sultry, reassuring voice asks listeners to "let your mind drift with me for just a minute".
Alright, alright, alright!
"Before we begin, as you settle in under the covers, with your head easing into the pillow, and your body sinking into the mattress … let's ask the question," he says.
In his trademark philosophical style, the Texas-born actor then launches into a series of musings about whether the listener has ever stopped to "ponder the depth of the present moment", to be inspired by the universe around them.
By this time, most listeners are so enraptured by McCounaghey's seductive vocalisations, that their thoughts are probably off on their own intimate journey of time and space.
Between The Wedding Planner, Failure to Launch and Magic Mike, how is anyone supposed to get any sleep around here?!
Many claimed the irresistibly handsome actor — who was voted People's Sexiest Man Alive in 2005 — did quite the opposite of winding them down for sleep.
Others thanked the actor for providing his Southern-style ramblings for the good of the world, with many asking for him to record more Sleep Stories.
The classic McConaughey jokes also rolled in, with many referring to his universally acknowledged catchphrase, coined in Dazed and Confused: "Alright, alright, alright!"
"I could listen to this, all night, all night, all night," one fan said.
The Magic Mike star's acclaimed bedtime story is only accessible by subscribers, who a required to fork out about NZ$66 per year.
It comes after Calm raised a mammoth NZ$28 million — invested by Lightspeed Venture Partners — to launch their Sleep Stories feature.
Lightspeed Venture Partners' spokeswoman Nicole Quinn said she was blown away by the spike in engagement after celebrity bedtime stories like McConaughey's were released on the Calm app.
"It was incredible to see the engagement spike up and also the retention," Quinn told TechCrunch.