Tom Hanks shared a picture showing a bag of the blood plasma he donated to researchers after overcoming coronavirus.
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.