Ronald Reagan's Son Slams Will Ferrell Movie About His Dad's Alzheimer's

"You should be ashamed," Michael Reagan said.

Comedian Will Ferrell is set to play Ronald Reagan in an upcoming biopic on the president and many are not thrilled about the casting.

Read: Saying Goodbye to Nancy: Casket Carrying Former First Lady Arrives at Reagan Library

Ferrell, who has spoofed President George W. Bush on Saturday Night Live and on Broadway, has been tapped to play the 39th president in a comedy called Reagan.

The film will spoof Reagan’s second term in office when some say, he was already showing signs of the Alzheimer’s disease that eventually killed him.

His oldest son, Michael, denies that is father had Alzheimer’s in the White House and he’s outraged by the movie's theme.

He tweeted:

In an open letter to Ferrell, Reagan's daughter, Patti Davis, wrote: "Perhaps you have managed to retain some ignorance about Alzheimer's and other versions of dementia. Perhaps if you knew more, you would not find the subject humorous."

Screenwriter Jon Spaihts announced the project on YouTube, saying: “When Ronald Regan falls into dementia at the start of his second term an ambitious intern is tasked with convincing the Commander-in-Chief that he is an actor playing the president in the film."

Gail Hodges-Burke, who was Nancy Reagan's social secretary during her time in the White House, spoke to IE about the film.

"I am a big fan of Will Ferrell's but the subject matter is not a funny subject matter," she said. "Look, I am not a comedian, I don't know how you blend all of those emotions together. I would guess it would be very difficult."

Read: Staff Remember Nancy Reagan's Devotion To Ronald: 'We Should All Be So Lucky To Have a Love So Deep'

Hodges-Burke said she did not see any signs of the disease in Reagan while he was in office. 

Ronald Reagan, who famously traveled from Hollywood into politics, wasn't officially diagnosed with Alzheimer’s until 1994, five years after he left the White House. He died in 2004.

Watch: Former Presidents, Hollywood Stars Gather to Say Goodbye To Nancy Reagan