'Up until an hour ago, the scariest thing I'd ever watched was Psycho,' tweeted J.K. Rowling.

President Donald Trump held a wide-ranging press conference Thursday, during which he insulted the media, defended former National Security Adviser Michael Flynn, and called reports of his contact with Russia "fake news." The president's performance, described by CNN's Jake Tapper as "unhinged," wasn't well received by celebrities.

Alec Baldwin, who plays Trump on Saturday Night Live, and Harry Potter author J.K. Rowling were among those who spoke out about the press conference. Rowling tweeted, "Up until an hour ago, the scariest thing I'd ever watched was Psycho. #TrumpPresser."

"This guy is so wired in front of the press," Baldwin wrote. "Imagine what he's like behind closed doors…"

While more celebrities chimed in online, Tapper, who recently had a contentious back-and-forth with Trump adviser Kellyanne Conway, reacted strongly on his network.

"It was unhinged; it was wild," he declared. "I can't believe there are Republicans on Capitol Hill and in the White House who don't understand that might play well with the 44 percent of the population that voted for the president, but a lot of Americans are going to watch that press conference and think, ‘That guy is not focused on me and I don't even know what he's focused on.'"

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