The couple were some of the first high-profile cases of Covid-19, falling ill while in Australia where Hanks was making a new Baz Luhrmann movie about Elvis Presley.
They kept fans updated on their condition and fully recovered, then allowed to return to their Los Angeles home.
When they arrived home, both enrolled in a medical study to test whether their antibodies would help scientists working on a vaccine.
Now Hanks, 63, has revealed they have both been approved to donate blood as they "do carry the antibodies".
He hopes his and his wife's blood is useful in the fight against the virus and has joked that if so, he'd be responsible for the creation of a "Hank-ccine".
"We just found out that we do carry the antibodies," he told hosts on the radio show.
'We have not only been approached; we have said, do you want our blood? Can we give plasma? And, in fact, we will be giving it now to the places that hope to work on what I would like to call the Hank-ccine."
The actor previously revealed that his wife suffered much more severe symptoms than he had.
"Rita went through a tougher time than I did. She had a much-higher fever and she had some other symptoms.
"She lost her sense of taste and smell. She got absolutely no joy from food for a better part of three weeks. She was so nauseous, she had to crawl on the floor from the bed to the facilities. It lasted a while."
