Sunday marked the 10-year anniversary of Adele's breakthrough album, "21," which debuted Jan. 24, 2011. The album set multiple records, earned numerous awards and was the best-selling album in both 2011 and 2012.

Adele marked her second studio album's milestone anniversary with a rare Instagram post, which featured a tribute to "21." The singer began, "Well I never! Happy 10 years old friend!"

The 15-time Grammy winner continued, "It’s crazy how little I remember of what it was like and how I felt a decade ago. But Thank You from the bottom of my heart for letting us into your lives and letting me be a soundtrack to some of it."

She sealed her dedication with a fond "x," which is commonly used in the U.K. to represent kisses.

"21" is widely credited for catapulting Adele, now 32, into the spotlight. The album, her follow-up to her 2008 debut "19," spawned hits "Rolling in the Deep," "Someone Like You," "Rumour Has It" and "Set Fire to the Rain."

It won best pop vocal and album of the year at the 2012 Grammy Awards, where "Rolling in the Deep" also won record of the year and song of the year.

The album also cemented Adele several Guinness World Records and, in the U.S., is currently certified platinum 14 times by the RIAA, having sold 14 million copies to date.

"21" went on to become the best-selling album in the U.S. for two years straight, the first album to achieve such an honor since Michael Jackson's "Thriller," which ruled the charts in 1983 and 1984.