VIDEO: Sneak Peek - J.R. Martinez Makes Special Appearance on ABC's EXTREME MAKEOVER

EXTREME MAKEOVER: HOME EDITION returns with a new primetime holiday-themed special episode with Ty Pennington and the team of designers, "Harris Family, Parts 1 & 2," MONDAY, DECEMBER 17 (8:00-9:00 & 9:00-10:00 p.m., ET) on ABC. J.R. Martinez makes a special appearance on the episode. Get a sneak peek below!

On February 19, 2007, while on patrol in Iraq, a massive IED struck the truck that SSG Shilo Harris was traveling in, tearing it apart. Yet despite suffering devastating injuries, with burns to over 40% of his body, Shilo's only concern was for the wellbeing of the men under his command, refusing medical treatment until he'd been assured that his troops were out of harm's way. During the months of painful surgeries that followed, Shilo and his loyal wife, Kathreyn, found a true calling -- to help wounded warriors through the agonizing and traumatic processes of recovery, rehabilitation and learning to face a life that will never be the same. Shilo, once sufficiently healed, began a career as a motivational speaker, giving hope to others similarly wounded, while Kathreyn, taking up the cause as well, began working for the Army Wounded Warrior Project. Shilo and Kathreyn have dedicated their lives to giving back.

With each day that passes the Harris family put more distance between themselves and the event that changed their lives, but their home still stands as a reminder of their struggles, as it cannot protect Shilo from dangerous dust and heat. The family have tried everything to make the home comfortable and safe, but whatever they do, it's not enough. This hero who was disfigured in service to his country cannot find respite in his own home.

J.R. Martinez, actor, motivational speaker and former U.S. Army soldier, makes a special appearance, and country music superstar Lee Greenwood performs "God Bless the U.S.A." in this moving holiday-themed tribute to our wounded veterans.

The "EM:HE" design team has just seven days to build a new home for the Harris family, as they are whisked away on a dream vacation to New York for a NYC Christmas extravaganza while team leader Ty Pennington, designers Paige Hemmis, Michael Moloney, Xzibit and Ed Sanders, along with local builder Morgan's Wonderland and Helping a Hero, and community volunteers, build the structure. "EM:HE" is produced by Endemol USA. David Goldberg is Chairman, Endemol North America. The series is executive-produced by Brady Connell & George Verschoor. This program airs in HD with 5.1 audio, and carries a TV-PG parental guideline.