The slogan took off in conservative circles after NASCAR driver Brandon Brown was interviewed by NBC Sports reporter Kelli Stavast about his victory at the Talladega Superspeedway in Alabama on Oct. 2. The crowd behind the interview began to chant the expletive directed at Biden, but Stavast responded: "You can hear the chants from the crowd, 'Let's Go Brandon!'"

Since then, the euphemism "Let’s go Brandon" has been repeated by a number of prominent figures on the right and Republican members of Congress have even shouted it from the House floor. When the president travels, he is often met by protesters holding "Let's Go Brandon" signs. During a campaign event for Virginia Democratic gubernatorial candidate Terry McAuliffe earlier this fall, protesters interrupted the president's speech with "Let's Go Brandon" chants.

Jill Biden's spokesperson Michael LaRosa called the use of the slur during the Christmas eve call "sick, tasteless, classless, disrespectful, juvenile, & appalling behavior for a parent (toward any commander-in-chief)," in a statement shared to Twitter on Sunday.

"But, no reasonable Democrat is actually shocked," LaRosa added. "Grateful for a @POTUS and @FLOTUS w/dignity and class who set an example for our kids (and parents)."