The Sherlock star burst out laughing as he read a Twitter troll's insult, in which the anonymous critic compared the actor's face to a ''cat's anus''.

The message read: "If you find Benedict Cumberbatch attractive, I'm guessing you'd also quite enjoy staring directly at a cat's anus."

The actor regained his composure, looked sternly into the camera and shot back, "Yeah, well someone did, and she put a ring on it!"

Cumberbatch wed theatre director Sophie Hunter earlier this year and the couple welcomed a son in June (15).

The Brit joined Jeff Bridges and Kristin Bell in the first segment of a week-long 'Mean Tweets Live' skit on Kimmel's late night show.

The mean tweeters suggested Bridges was seriously unhinged and Bell's vagina was "an Alcatraz for penis (sic)".