The Secretary of State for Scotland "liked" a tweet by an American internet personality, James Charles, that raised eyebrows among some.
The tweet said: "all I want for christmas is a good d*** to s*** tbh".
The original tweet was liked by around 200,000 other people aside from the Tory MP.
The Scottish Conservative MP for Dumfriesshire, Clydesdale and Tweeddale later removed the "like" after it had gathered attention on the social media platform.
He then tweeted: "Big thumbs always a twitter issue at any time of year" along with a Santa Claus emoji and a winking face.
After Twitter users spotted the surprising festive favourite, it soon went viral.
Many users sent their own Christmas wishes to the MP, with some sending screen shots of the offending tweet.
One user posted a screen shot to Mr Mundell of his interaction with the explicit tweet, which he then liked himself.
He has since unliked the original tweet.
A version of this article originally appeared on i News