Celebrity TV host Ellen DeGeneres called out US President Donald Trump, following his attack on TV and entertainment icon Oprah Winfrey in a tweet.

DeGeneres posted a clipping from her show and captioned it: “You mess with Oprah, you mess with me, Mr. President.”

During an appearance on “60 Minutes”, Winfrey quizzed a group of Michigan voters. Half of the people from the group voted for Trump in the 2016 presidential election, the other half did not.

“One year into Donald Trump’s presidency, Americans remain divided, often unwilling to listen to what the other side has to say,” Winfrey said.

Hours after the episode was aired, Trump tweeted: “Just watched a very insecure Oprah Winfrey, who at one point I knew very well, interview a panel of people on ’60 Minutes’.”

“The questions were biased and slanted, the facts incorrect. Hope Oprah runs so she can be exposed and defeated just like all of the others!” he wrote.

Not taking the president’s tweet lightly, DeGeneres said on her show on Thursday: “President Trump, it’s time for an a-ha moment. You’re not just some guy on Twitter anymore – you are the president for all of us. It is your job to unite people, and you don’t do it by attacking people, especially Oprah.”