Some children of US servicemen killed in combat are giving their late dads a special gift this Father’s Day: a letter telling them how much they still mean to them.

Children of Fallen Patriots, a charity that has paid college tuition for hundreds of children who lost a parent in the line of duty, has been using the idea as a grief exercise this year, allowing the now-young adults to express what they wish they could tell their parent in person.

Henry Danny Irizarry, 28, chose to keep things short and sweet in his touching note to his father, who was killed in Iraq 14 years ago.

“Dear dad,” wrote Irizarry, now an NYPD cop. “The most important skill you taught me was to learn how to think. The second most valuable was to learn as much skill as possible.

“I have achieved so much in life just by having these two side by side,” Irizarry added. “I thank you for every moment we spent together and will continue to share the same love you showed me to others around me. Your son, Henry.”

Irizarry told The Post that he vividly remembers the last time he saw his father, Henry Edison Irizarry, who was killed on Dec. 3, 2004, when an improvised explosive device detonated near the Humvee he was driving.

“What will you do when you grow up?” his dad asked just days before his deployment.

“I’ll be a police officer,” Irizarry recalled answering, as the duo fixed a sink together in their Bridgeport, Conn., home. “I’ll grow up to save people, just like you do.”

For Father’s Day, Irizarry said he wishes he could also tell his father that he kept his word — and then some.

Irizarry not only became a cop — he’s an officer with the NYPD’s elite Critical Response Command unit and just passed his written sergeant’s exam.

“I wish he could see me in uniform,” he said. “I know he’d be proud.”

Haley Hartwick, 22, referred to her dad as her “pilot” and “hero” while writing to him this week.

“You still serve as my inspiration and the person that feels my passion,” she wrote. “I only hope to make you proud and continue to achieve the dreams you had for me.”

Haley lost her father — US Army Chief Warrant Officer Michael Hartwick — in 2006 during Operation Iraqi Freedom.

“Your service and sacrifice will never be forgotten nor your bravery and courage,” she wrote. “Just like you told me in your last letter to me all those years ago, I’m still taking care of Mom and Tanner and enjoying the Spring as well as the many other joys life has to offer. Love your little girl.’’

Haley and Irizarry were among nine people who penned letters to their late fathers as part of the Children of Fallen Patriots initiative. Some were written by hand, others typed — but they all got the same message across.

“Dad, I miss you. There is not a day that goes by when I don’t wish that you were here,” wrote Boston Gilbert, son of US Air Force Maj. Troy Gilbert, who was killed in a helicopter crash in 2006. “I will never forget your legacy, and I will never forget your sacrifice.”

Foundation spokesman Chris Petrakos said 20,000 dependents have been left behind by fallen troops over the past 35 years.