Despite living in London, Damian Lewis backed Wales over England to win the Six Nations, he revealed.
The Homeland star said he considers himself London-Welsh due to childhood "brainwashing".
The Emmy and Golden Globe Award-winning star said: "We have a strong Welsh connection in our family. We joke that we're London-Welsh."
Lewis, whose wife Helen McCrory also has Welsh roots, added: "We've got a house in Wales, we support the Welsh rugby team.
"I was supporting, in fact, the Welsh rugby team on Saturday, which is all part of my brainwashing as a child." Last weekend, Wales beat England 30-3 to win the Six Nations.
Lewis was speaking as he received the Freedom of the City of London today.