Who was Mary Mouser dating? All we know about ex Brett Pierce 

Cobra Kai stars Mary Mouser and Tanner Buchanan have announced their engagement. They shared the news on their respective Instagram accounts.

In a post shared on February 14, 2025, the pair posted heartfelt pictures:

“This is such a special moment in our lives, the closing of one chapter and celebrating the continuation of another. We’re so grateful for the love and support, and though we’re partial to having our private moments, we’re excited to share this check-in to our world.”

The lovebirds made their first public appearance as a couple at the premiere of Season Six, Part Three of the Netflix series on February 12, 2025, in Los Angeles. According to the reports, they revealed their engagement by showing off matching rings.

Previously, Mouser had been in a relationship with Brett Pierce since December 2015, as per Distractify. Reports of their breakup emerged in 2024. However, they never publicly confirmed the reports.

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Everything to know about Mary Mouser’s ex-boyfriend Brett Pierce

In December 2020, Mouser announced their fifth anniversary in a now-deleted Instagram post. She wrote:

“[F]ive years with you has felt like five minutes. [H]appy anniversary to the most spectacular boyfriend – who I am so grateful to say is also my best friend, my whole heart, and the only one I would want to be locked in a cabin with for the whole weekend,” according to a report in Entertainment Now.

Actor Brett Pierce was born on May 31, 1991. He was a star athlete at Brentwood High School, where he played football and baseball. He had also performed at Carnegie Hall in New York City. He studied film and theatre at the University of Southern California, per his IMDb profile.

Pierce appeared as Cuff in the Disney Channel show Stuck in The Middle, which aired from 2016-2018 and also starred Jenna Ortega. The series revolved around Harley Diaz, the middle child in a family of seven, who used her inventive skills to navigate life in her large family.

He also played the role of Young Eddie in the ABC TV series, A Million Little Things, which aired from 2018-2023. He later appeared in Season 14 of Grey’s Anatomy.

He also made notable appearances in series such as Scorpion and This Just In.

Mouser and Pierce had been public about their romance and frequently shared pictures on social media. They supported each other throughout their relationship and were spotted at several events together.

Rumors of their breakup emerged when they stopped posting about their lives on social media. Reportedly, Mouser’s last post with Pierce was from Christmas 2019.

Before Mary Mouser and Tanner Buchanan’s recent announcement, fans speculated a romance between the couple, but they were reportedly labeled “friends.”

In Cobra Kai, Mary Mouser plays Samantha "Sam" LaRusso, the daughter of Daniel LaRusso, the original Karate Kid, while Buchanan plays Robby Keene, the son of Daniel's longtime rival, Johnny Lawrence.