Martin Freeman has admitted his regret over smacking his children and calling them "little f***ers" when they were younger.
The Sherlock and Hobbit star, 48, shares children Joe, 14, and Grace, 11, with his former partner Amanda Abbington, 45.
Martin said Amanda made not smacking and not swearing the children two of the rules in their house but that he still did both more than once.
But he opened up about how much he regrets his past actions.
In a candid chat with The Sunday Times, he said: "I know I'm not supposed to do it, but there are so many images about how [parenting] all just has to be brilliant that it makes people feel bad.
"Because it's not brilliant. I mean, it is - it's the best thing I'll do. But that doesn't mean it's not really hard. This idea you only ever rationalise with a toddler? Genuinely, good luck. If you could do that, God go with you. Amazing.
"I'm not proud I did that, but I have. I don't think it's a policy. And I'll do it again!"
Under The Children Act 2004 it is illegal to smack children unless it amounts to "reasonable punishment".
Children's charity the NSPCC has called for a complete ban on smacking, saying they believe it only sets a bad example for children on how to deal with strong emotion.
Charity bosses also feel that smacking could encourage bullying as well as cause children to lie or hide their true feelings in fear of the punishment they might receive.
Martin, who starred in Sherlock alongside his now-ex Amanda, previously admitted working on the show "wasn't much fun" while they were going through their break up.
They played married couple John and Mary Watson on the hit BBC show before and after their split in 2016, after 16 years together.
Martin once told BBC Radio 4's Desert Island Discs: "We met on a set in 2000, we met on a Channel 4 drama called Men Only and we clicked immediately.
"We just hit it off, we went on a date a day or two later and we were together for 16 years.
"She was and remains one of my favourite actors, I think she's a fantastic actor."
Asked how it was to work with her on Sherlock, he replied: "Awful! No, it was good, I really love working with her.
"By the time of the last Sherlock that we've done we were sort of in the midst of splitting up, so that wasn't that much fun, but when we weren't in that midst it was great."
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