Colin Farrell thinks Ewan McGregor should be more proud of his penis.

The 38-year-old actor says his 'Cassandra's Dream' co-star - who has stripped in several of his movies - is very well-endowed and should ''wear it like a badge of honour'' rather than being modest about his manhood.

He told Nylon Guys magazine: ''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 honour.''

Meanwhile, Ewan - who raises daughters Clara, 18, Esther and Jamyan, both 14, and four-year-old Anouk with wife Eve - has warned his children off getting tattoos until they are much older.

He said: ''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.'''

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

He told the publication: ''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.''