Meghan Trainor joined Kelly Clarkson on the Kellyoke stage on Monday for a stellar performance of her hit 2014 debut single “All About That Bass.”

The Title singer celebrated the track’s 10th anniversary with the host, who noted that it was the “best-selling song by a female artist of the previous decade.” Trainor’s doo wop-inspired song reached Number One on the Billboard Hot 100, where it spent eight consecutive weeks.

The pair harmonized effortlessly as they sang, “My mama she told me don’t worry about your size/She says,...