Arnold Schwarzenegger and Reese Witherspoon were among the US stars marking Memorial Day.
The federal holiday, observed annually on the last Monday in May, honours military personnel who died in the line of duty.
Americans attended memorial services across the country throughout the weekend, with President Joe Biden delivering a speech at Arlington National Cemetery in Virginia.
Celebrities marked the occasion on social media.
Oscar-winning actress Witherspoon tweeted: “Thank you to all the servicemen and women who have gone above and beyond to protect our country. Today and everyday, I honour you.”
Schwarzenegger, an Austrian-born Hollywood action hero and former governor of California, shared a video message on Instagram.
Wearing a stars and stripes cowboy hat, he explained the history of Memorial Day, telling fans it started as “decoration day” after the American Civil War.
He said: “Today we honour the heroes who made the ultimate sacrifice for our country. Thank you, thank you, thank you.”
Actor Mark Wahlberg shared a picture of a soldier placing US flags at military graves and wrote: “Respect. Honour. Remember.”
Halloween actress Jamie Lee Curtis said the message of the day is Americans are “stronger together”.
She wrote on Instagram: “That through the strength, courage, bravery and sacrifice so many made to preserve this experiment in freedom and democracy, the greatest gift we can give them back, besides our respect, is to connect to them and thank them for their service if they are still here.
“We all have our national pride flags of our parent’s ancestry and ours. I fly them all today!”
Actress, director and producer Mindy Kaling shared her support for the Wounded Warrior Project, a charity helping veterans.
She said: “Thinking of the courageous men and women in the military who sacrificed their lives for our country. Love to the families they left behind. I especially want to send encouragement and gratitude to the soldiers who keep the marks of battle on their bodies and minds, my heart goes out to you.”
Kris Jenner, matriarch of the Kardashian-Jenner family, said Memorial Day was a time to “remember the heroes who have fallen, the brave men and women who sacrificed their lives for our country and our freedom”.
She added: “We honour them today, and thank them and their families.”
Hollywood star Chris Pratt shared a lengthy post alongside pictures of mourners grieving for fallen military personnel.
He said: “They have given us the most free and decent society planet earth has ever seen. We run the risk of losing that decency when we fail to instill gratitude in the minds of our youth or the perspective of what it actually means to be free- should they never learn of the selfless sacrifice of our armed service members in the face of oppressive evil.
“So join me in showing support for our fallen. Take a quiet moment to really consider the sacrifice.”