The House star said he never thought the virus could live inside him because the alcohol in his system would have killed it in the past.
He told talk show host Ellen DeGeneres, 'I do have a cold.
'But I'm very excited about having a cold because it's my first one ever.
'It absolutely is true.
'I promise you. It's the first cold of my whole life.'
Hugh - who plays Dr Gregory House on the hit TV show - joked, 'And I'm excited because for so many years I believed basically nothing could live in this body because I was so addled with booze and cigarettes.
'But now it appears I have curb appeal after all.
'I don't know how I got it.'
The actor also told how he diagnoses other people even though he has no medical qualifications.
'I offer all kinds of medical advice, without any grounds whatsoever,' he quipped.