The West Wing actor Richard Schiff said he has been taken to hospital after testing positive for Covid-19.
The 65-year-old, best known for playing White House communications director Toby Ziegler on the political drama, revealed earlier this month he had the illness.
In an update, he thanked fans for their support and said he is in hospital, where he is taking the antiviral medication Remdesivir.
He tweeted: “I am in the hospital on Remdesivir, O2 and steroids showing some improvement every day.”
Schiff said his wife Sheila Kelley, who also has Covid-19, is at home but “still fairly ill”.
She shared her own update, saying the last 72 hours had been “tough”.
Kelley, 57, added: “Thank you all of you for the prayers and love. We feel them. He’s doing better. Getting stronger.”
The actress, who has two children with Emmy-winner Schiff, detailed her experience with the virus.
She said: “My son and I are still riding this strange covid coaster up and then down and all around.
“I have never experienced anything like this before in my life. One minute I’m feeling pretty good and the next I’m struggling to breathe.
“What I do know is if you get this virus the relationship between you and your body is everything.”
The couple are the latest celebrities to publicly confirm they have tested positive for the virus.
Tom Hanks and his wife Rita Wilson were among the first to do so, revealing the news on social media in March.