background song in the MAC Cosmetics Studio Fix ad

If you've been on social media or watched television anytime in the last year, you've likely seen it: Kris Jenner, in a chic black ensemble, power-walking on a treadmill while expertly shaking a martini. Her makeup? Impeccable. Her expression? Utterly unbothered. She glances at the camera with that signature blend of authority and amusement, and for thirty seconds, the internet stops to watch.

The MAC Cosmetics "Martini Test" commercial for Studio Fix foundation became an instant viral sensation. It spawned countless memes, parodies, and a renewed appreciation for the "momager" as a cultural icon. But a huge part of its appeal—the secret ingredient that makes the whole thing stick in your brain—is the infectious, upbeat track playing in the background.

So, what is the background song in the MAC Cosmetics Studio Fix ad?

The song driving this iconic moment is "Fun" by Cortisa Star. Let's dive into why this track was the perfect choice, explore the campaign's different versions, and see how music and makeup combined to create a cultural moment that transcended the beauty world.

1. The Song: "Fun" by Cortisa Star

The background music in the main "Martini Test" commercial is "Fun," a vibrant, energetic track by artist Cortisa Star. While it may not be a ubiquitous pop anthem topping the Billboard charts, the song is a perfect piece of production music that captures a specific, sassy, and unstoppable mood. It sounds like confidence in audio form.

The Vibe: Confident and Playful

"Fun" is built on a driving, infectious beat that immediately makes you want to move. Layered over that are funky, wah-wah pedal-infused guitar riffs and a punchy brass section that feels straight out of a 1970s blaxploitation film soundtrack—think Shaft meets a modern dance floor. The whole track has been expertly updated for a modern audience, giving it a fresh, contemporary feel while nodding to a classic era of cool.

The tempo is brisk and purposeful, perfectly matching Kris Jenner's determined stride on the treadmill. Every step she takes seems to land on the beat. The overall feeling is one of playful, unshakeable confidence. It’s the sound of someone who is in complete control, having a great time, and knows exactly how good they look while doing it. It’s impossible to listen to "Fun" without cracking a smile or feeling a surge of energy.

Why It Works So Perfectly

The song's title, "Fun," is deceptively simple, yet it perfectly underscores the campaign's core message. Wearing MAC Studio Fix is presented as so easy, so reliable, that you can literally put it through a grueling stress test (a treadmill workout combined with the precarious art of cocktail shaking) and still have a blast while doing it.

The music tells you, the viewer, that this foundation isn't a burden, a mask, or something to worry about. It's a partner, a tool that lets you enjoy your life and your ambitions, no matter how chaotic or demanding they get. The brass stabs punctuate Kris's dramatic movements—a flick of the wrist, a knowing look—and the rhythm drives the narrative forward, transforming a 30-second product demonstration into a mini-movie with a clear, joyful hero.

You can watch the viral video and hear the song in action here:

Kris Jenner | "The Martini Test" (Main Ad):

Watch YouTube video

2. The Extended Version: "Works Harder"

The overwhelming success of the initial spot led to an extended version of the commercial, often referred to as the "Works Harder" cut. This version doubles down on the winning concept, giving viewers more time with Kris and her now-famous martini-shaking, treadmill-strutting routine.

Maintaining the Musical Momentum

Crucially, this longer format retains "Fun" by Cortisa Star as its sole musical backdrop. This consistency is key to building a strong brand identity. By using the same track across all versions, MAC ensures that the powerful association between the song, Kris Jenner, and the Studio Fix foundation is reinforced every single time a viewer encounters any iteration of the ad.

The extended cut allows the song to breathe and develop. We get to see more of the "stress test" elements in greater detail—more treadmill time with increasing speed, more intricate steps in the martini preparation, and more of Kris's signature deadpan stares directly at the camera, breaking the fourth wall with impeccable comedic timing.

The music keeps the energy high and the tone consistently light and playful, preventing the longer runtime from feeling draggy or repetitive. It proves that a truly great track can support an extended narrative without losing any of its punch. In fact, it enhances it, giving us more time to live in the gloriously fun world the ad has created.

Watch the extended version and see how the song drives the longer narrative here:

Kris Jenner | Extended Version ("Works Harder"):

Watch YouTube video

3. The Supporting Content: The Shade Clip (NC20)

Beyond the main commercials and their extended cuts, MAC also released a wave of supporting content that cleverly capitalized on the campaign's massive popularity. One particularly notable and practical piece is a short, focused clip dedicated to the exact shade Kris Jenner wears in the video: MAC Studio Fix in shade NC20.

Music as a Cohesive Branding Tool

Even in this brief, informational clip—which is essentially a digital shade swatch for curious consumers—the powerful musical identity of the campaign remains intact. A short, instantly recognizable snippet of "Fun" by Cortisa Star plays in the background, serving as an audio logo.

This is a savvy and often overlooked marketing move. By keeping the same music playing even in a simple, utilitarian shade-reveal video, MAC creates a seamless and cohesive audio brand experience. When consumers hear that funky beat and those unmistakable horns, even for a few seconds, their brains are immediately triggered to think of Kris Jenner, the martini test, and the foundation's incredible staying power.

It transforms what could have been a mundane piece of content (a shade reference card, essentially) into an integral part of the larger, more exciting campaign narrative. It reinforces the message that every touchpoint with the brand, no matter how small, exists within the same confident, playful world.

A Practical Takeaway for Fans

This clip also serves a very practical purpose for consumers. Knowing that Kris Jenner, the iconic "momager" herself, wears NC20 provides a hugely helpful and relatable reference point for fans and makeup shoppers looking to find their own perfect match. It adds a layer of personal connection—"If it's good enough for Kris, and that's her shade, maybe it's the right one for me too."

You can see the exact shade and hear that iconic background music snippet here:

Kris Jenner's Shade (NC20) Clip:

Watch YouTube video

The Bigger Picture: Music as the Secret Ingredient

The runaway success of the MAC Studio Fix "Martini Test" campaign is a perfect case study in how all the elements of modern advertising need to work in perfect harmony.

You have a compelling, unexpected star in Kris Jenner, who brought her unique cultural cachet and deadpan humor to the role. You have a clever, visually memorable concept that brilliantly demonstrates the product's key benefit (long-lasting, sweat-proof, transfer-resistant foundation) in a way that is entertaining, not preachy. And, crucially, you have a soundtrack that ties it all together and provides the emotional engine.

"Fun" by Cortisa Star is emphatically not just background noise. It is the emotional core of the ad. It tells you, the viewer, exactly how to feel while you're watching. It injects pure energy, sass, and a palpable sense of joyful invincibility into every single frame. Without it, Kris Jenner would just be a woman on a treadmill holding a cocktail shaker—an odd, slightly confusing image. With it, she's an unstoppable icon, and the foundation becomes the essential tool for anyone who wants to channel that same unstoppable, fun-filled energy in their own life.

So, the next time you see that commercial pop up on your feed, you'll know the name of the song. More than that, you'll understand that the music is doing just as much work as the makeup—cementing a mood, building a brand, and making sure you remember the moment, and the product, long after the video has ended.