Michael J. Fox paid a virtual visit to “The Graham Norton Show” to share an anecdote about how his son gave him a pithy response that instantly shut down a rude Twitter troll.

Speaking with host Graham Norton, the “Back to the Future” star admitted he’s not particularly savvy when it comes to the internet.

As he explained, his daughters had been taking care of his Instagram posts “and my son is there to kind of troubleshoot” on social media.

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“I got on trouble on Twitter [when] somebody said something nasty about Parkinson’s,” added Fox, who was diagnosed with the disease when he was just in his late twenties.

“I usually just let that stuff go by me, doesn’t happen that often, when it does I don’t really care about it,” he added.

“But I wanted to answer this guy in some way, so my son said, ‘Just do this, do SMH.’ And I said, ‘Whattaya mean SMH?’ And he said, ‘Trust me, do SMH,'” Fox continued.

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“So I answer the guy back SMH, and he answers me back, this is the funniest thing I’ve ever read in my life, ‘You’re the king of the internet, I apologize for anything I said to you, blah blah blah blah,’ and I said to my son, ‘What the s**t did you say?'” he said. “And he said, ‘Shaking my head.'”