Oscar-winning actor Jeremy Irons says he should have “buttoned” his lip when he joked equal marriage could lead to fathers marrying their sons, although he now admits that he doesn’t know the difference between a same-sex marriage and a civil partnership.

Earlier this month, Irons, 64, suggested to Huff Post Live that equal marriage legislation could be manipulated to allow fathers to pass on their estates to their sons without being taxed.

“Could a father not marry his son?” Irons asked host Josh Zepps.

When reminded about laws preventing incest, Irons replied: “It’s not incest between men”, because “incest is there to protect us from inbreeding, but men don’t breed.”

Appearing on yesterday’s Hardtalk programme, Irons said that his strong opinions often get him into trouble.

“I felt I should have buttoned my lip, I was just flying a kite,” Irons told Stephen Sackur, regarding his previous comments to the Huffington Post.

“I didn’t have any opinion about gay marriage…I don’t actually have much opinion about heterosexual marriage, except I possibly think it might protect children and make it easier for children, that’s why I married my wife,” Irons said. “Gay marriage is not something I have any feelings about at all; I’m quite interested in what it does to marriage, which is why we were having this rather bizarre conversation.”

When Sackur quizzed Irons about his previous comments of equal marriage “debasing” the institution of marriage, the actor replied: “Well it changes it doesn’t it? I mean marriage is about procreation, really that’s how historically it has always been…but I’m actually very badly informed I don’t know the difference between a civic [sic] partnership which we have in this country – a civil partnership – and marriage which the government has just voted on, I don’t know what the difference is?”

Irons added: “I know the church has problems with it historically, and I don’t know if those problems will go away, in America I think it’s different because in some states you can marry same-sex partners and in some states you can’t.”

Referring back to his original comments on fathers marrying their sons, Irons said: “I was just rather amused by the idea, which I put forward, it had nothing to do with my feelings.

“I think gay marriage is wonderful…as I said at the end of that interview – and this wasn’t reported – ‘any [thing] which holds anybody together is great”.