(CNN) The Twitterverse lit up Monday morning over model Chrissy Teigen's response to an attack from President Donald Trump, an exchange that was heated even by the standards of his routine social media fights.

The spat began when the President, apparently venting about a town hall on criminal justice reform that aired on MSNBC Sunday night, tweeted that he and other Republicans should be getting more credit for signing the First Step Act into law.

The legislation, signed back in December, includes measures that allow thousands of federal inmates to leave prison earlier than they otherwise would have, eases some mandatory minimum sentences and gives judges more leeway in sentencing, among other things. It had support from lawmakers from both sides of the political aisle and received personal attention from Trump's son-in-law and senior White House adviser Jared Kushner.

"I SIGNED IT INTO LAW, no one else did, & Republicans deserve much credit. But now that it is passed, people that had virtually nothing to do with it are taking the praise," the President tweeted late Sunday night.

Then Trump went after singer and activist John Legend (who appeared in the MSNBC town hall) and his wife Teigen.

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