Niall Horan has accused Health Secretary Matt Hancock of being "smug and slippery" despite having committed a "major howler" in his response to coronavirus.
The singer posted his stinging criticism of Matt Hancock to his 39 million Twitter followers.
He said: "I get the idea that Health Secretary Matt Hancock thinks he's a lot more intelligent than he actually is.
"Always very smug and slippery.
"Excuse me but Matt you've had a major howler here and it's about time you handed facts out instead of worrying about what the opposition thinks."
Last month, Horan, 26, performed in the One World: Together At Home virtual concert, which celebrated frontline workers fighting the coronavirus crisis and raised money for the UN Foundation's Covid-19 Response Fund.
He has also made a 100,000 euro (GBP 88,478) donation to Alone, which is an Irish charity helping older people through the pandemic.