Oh my!

Colin Farrell, 38, says his 43-year-old 'Cassandra's Dream' costar, Ewan McGregor — who has stripped down in several of his movies — is very well-endowed and should "wear it like a badge of honor" rather than being modest about his manhood.

"I don't think Ewan is as proud of his penis as most men who are as well hung would — or should — or could be. I think that's the greatest demonstration of his innate humility, that he doesn't wear it like a badge of honor," Colin told 'Nylon Guys' magazine.

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Ewan on the February/March 2015 issue of 'Nylon.'

Meanwhile, Ewan — who has daughters Clara, 18, Esther and Jamyan, both 14, and Anouk, 4, with wife Eve — has warned his children to refrain from getting tattoos until they are much older.

"Clara, my eldest, started talking about tattoos. I said, 'Dude, I got my tattoo when I was 30 years old. You're 17? 18? I can assure you that what you think you want on your arm now isn't what you're going to want on your arm when you're my age. Don't do it,'" Ewan said.

Related Story: Colin Farrell Reveals His Romantic Side

Despite his lengthy career, the 'Mortdecai' star insists being a father is the "most important" part of his life.

"I've been a dad for 18 years. Your work reflects your life, and the biggest element of my life is that I'm a dad. That's the most important thing of all," he told 'Nylon.'

The February/March 2015 issue of 'Nylon' hits newsstands on Feb. 2.