Tom Hanks shared a picture showing a bag of the blood plasma he donated to researchers after overcoming coronavirus.
Tom Hanks donates his blood plasma following coronavirus diagnosis
The Hollywood star, 63, and his wife Rita Wilson were both diagnosed with Covid-19 last month and have since made a full recovery.
Hanks has donated his plasma – the liquid part of the blood – to scientists in California treating patients still fighting the disease.
The plasma from former patients is rich in the antibodies that develop as somebody recovers from an illness.
Hanks posted a picture of a bulging bag of the yellow liquid and wrote: "Here's last week's bag of plasma. Such a bag! After the paperwork, it's as easy as taking a nap."
He thanked UCLA and epidemiologist Anne Rimoin, a public health professor and director of the Centre for Global and Immigrant Health at the university.
Patients in the UK who have recovered from Covid-19 have also begun donating their plasma.
Hanks and Wilson were diagnosed with the virus while in Australia filming an Elvis Presley biopic he will star in.