7 Unbelievable Secrets Of Tanner Buchanan And Mary Mouser's 'Secret Romance' Leading To Their Shock Engagement

The most shocking plot twist in the world of *Cobra Kai* has nothing to do with Miyagi-Do or the final All Valley Tournament. As of late December 2025, the biggest news dominating pop culture headlines is the stunning, real-life engagement of co-stars Tanner Buchanan and Mary Mouser, who play the beloved on-screen characters Robby Keene and Samantha LaRusso.

For years, the two actors maintained a steadfast "just friends" narrative, expertly dodging questions about a real-life romance. That facade crumbled spectacularly at the series finale premiere, where they didn't just confirm they were dating—they announced they were engaged, instantly becoming one of Hollywood's most talked-about couples and delivering the ultimate fan-fiction ending to their secret love story.

Tanner Buchanan and Mary Mouser: Full Biography and Profile

The relationship between Tanner Buchanan and Mary Mouser is a classic Hollywood romance that began on a set, but their individual careers laid the groundwork for their stardom.

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Tanner Buchanan Profile

• Full Name: Tanner Emmanuel Buchanan
• Date of Birth: December 8, 1998
• Age (as of Dec 2025): 27
• Place of Birth: Lima, Ohio, USA
• Key Roles: Robby Keene (*Cobra Kai*, 2018–2025), Leo Kirkman (*Designated Survivor*, 2016–2019), Mason Kendall (*Game Shakers*, 2015–2019), Cameron Kweller (*He's All That*, 2021)
• Career Start: Moved to Los Angeles around age 9 to pursue acting.
• Relationship Status: Engaged to Mary Mouser.

Mary Mouser Profile

• Full Name: Mary Matilyn Mouser
• Date of Birth: May 9, 1996
• Age (as of Dec 2025): 29
• Place of Birth: Pine Bluff, Arkansas, USA
• Key Roles: Samantha "Sam" LaRusso (*Cobra Kai*, 2018–2025), Lacey Fleming (*Body of Proof*, 2011–2013), Karen Grant (*Scandal*, 2012), Eloise (*Freakish*, 2016)
• Career Start: Began her career as a child model and actress, with her first major role in 2202’s *Signs*.
• Relationship Status: Engaged to Tanner Buchanan.

The Five-Year Facade: From Co-Stars to 'Just Friends'

The love story of Tanner Buchanan and Mary Mouser is unique because of its long, carefully guarded secrecy. The two met in 2017 on the set of *Cobra Kai*, a show that would define their careers and their personal lives.

1. The Initial Meet-Cute on Set (2017)

When the series began filming, Tanner and Mary were quickly paired as love interests for their characters, Robby Keene and Sam LaRusso. Their on-screen chemistry was undeniable, fueling fan speculation from the very first season. Off-screen, they established a deep friendship that, according to recent revelations, quickly blossomed into something more.

2. The 'Just Friends' Narrative

For years, both actors were masters of misdirection. In countless interviews, they consistently referred to each other as "best friends," "like siblings," or "family." This narrative was so convincing that the public and media largely accepted it, even as they spent significant time together off-set, including joint appearances with other cast members like Jacob Bertrand and Peyton List. This allowed their relationship to grow privately, away from the intense scrutiny of the Hollywood spotlight.

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3. The Secret Romance Timeline

While the exact start date remains a private detail, the "secret romance" is believed by many fans to have begun around 2018, shortly after the first season of *Cobra Kai* premiered. They navigated the pressures of a high-profile show, a demanding filming schedule, and a loyal fandom that desperately wanted them to date, all while keeping their true status under wraps. This period of secrecy added a layer of intrigue that only amplified the eventual announcement.

The Shock Announcement: Engagement at the Series Finale Premiere

The end of *Cobra Kai* brought a beginning for its two biggest stars. The long-awaited final season premiere event in February 2025 served as the perfect, dramatic stage for their public debut as a couple and their engagement announcement.

4. The Red Carpet Reveal

Walking the red carpet for the series finale, Tanner and Mary shocked everyone. They arrived together, not just as co-stars, but as a couple, confirming their relationship with a public kiss. The real headline, however, was on their hands. Both actors were seen sporting matching diamond rings on their left hands, immediately sparking engagement rumors that they happily confirmed.

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5. A Joint Instagram Post Confirms the Betrothal

Following the event, the couple took to social media to make it official. In a joint Instagram post, they shared a photo of their matching rings and a heartfelt message. They confirmed that they were not only dating but were officially engaged to be married. The caption expressed their happiness at finally being able to share their "special moment" with the world after years of keeping it private.

6. The Real-Life Robby and Sam

The relationship between Tanner and Mary is a beautiful parallel to the complex, on-again, off-again dynamic of their characters, Robby Keene and Sam LaRusso. While their characters went through intense rivalries, breakups, and shifting loyalties between Miyagi-Do and Cobra Kai, the actors themselves built a solid, enduring foundation. Fans of the show, who have long "shipped" the pair, instantly celebrated the news, calling it the "ultimate *Cobra Kai* ending."

What’s Next for the Engaged Couple?

With the final season of *Cobra Kai* now concluding, both Tanner Buchanan and Mary Mouser are looking toward the future, both professionally and personally. Their engagement marks a significant new chapter for two actors who have spent the better part of a decade growing up on the same set.

7. Future Projects and Wedding Bells

While details about their wedding are scarce, the couple is expected to take some time to plan their nuptials following the promotional whirlwind for the *Cobra Kai* finale. Professionally, both are poised for major career moves. Tanner has already successfully transitioned to film with roles like the lead in the Netflix movie *He's All That*, and Mary continues to be a highly sought-after actress. Their combined star power as an engaged couple only increases their visibility for future projects, solidifying their status as Hollywood’s newest power couple.

The story of Tanner Buchanan and Mary Mouser is a testament to finding true love in the most public of places, yet managing to keep it a deeply personal "secret romance" until the perfect moment. Their engagement is not just a celebrity headline; it’s the happy, unexpected ending fans of the *Karate Kid* universe never knew they needed.