Prince Harry received a special birthday tribute at the Invictus Games.

While watching the sitting volleyball game between Poland and Germany with wife Meghan Markle at the international sporting event for ill and wounded military service members and veterans Sept. 15, the crowd sang a personalized rendition of "Happy Birthday" to the Duke of Sussex.

Just before he was serenaded in honor of his 39th birthday, the announcer wished Harry a happy birthday, prompting the Duchess of Sussex, 42, to clap and rub her husband's shoulders as he smiled, clapped and gave a double thumbs up.

The sixth annual Invictus Games, which Harry founded in 2014, were held in Düsseldorf, Germany.

On the first day of this year's event Sept. 9, Harry had given an opening speech, during which he joked about his and Meghan's enthusiasm for the games ahead. "Now, I'm not saying we play favorites in our home," he noted, "but since my wife discovered she's of Nigerian descent, it's likely to get a little bit more competitive this year."

While Meghan was in California with the couple's kids Prince Archie, 4, and Princess Lilibet, 2, at the time, she soon joined her husband in Germany.

"It is so special to be here, and I'm so sorry that I was a little late for the party," she said at a dinner for the athletes' friends and family Sept. 12, according to Hello! "Just like so many of you, we know this is about family and friends and the community that Invictus has created, that Fischer House has created, and so I had to just spend a little bit more time getting our little ones settled home, getting milkshakes, doing school drop off, and then I landed a couple of hours ago."

She continued, "I'm really proud to be part of this Invictus family with all of you. I'm grateful for all of you that are here."

Since reuniting at the Invictus Games, Harry and Meghan have attended several events together, including the wheelchair basketball finals and the time trial and criterium cycling competition.

Scroll down for Harry and Meghan's cutest moments at the 2023 Invictus Games:

The Duke of Sussex gets serenaded by the crowd at the sitting volleyball game between Poland and Germany with a personalized rendition of "Happy Birthday." Harry turned 39 that day.

The pair meet a new friend at the Time Trial & Criterium Cycling event.

The Duke and Duchess of Sussex were side-by-side while at the medal ceremony for the Wheelchair Basketball Finals.

The royally cute couple stopped to snap a selfie while visiting the Kids' Zone at the Merkus Spiel-Arena.

The pair were seen holding hands as they met with the NATO Joint Force Command and families from Italy and the Netherlands.

Harry and Meghan were engrossed in conversation as they watched the volleyball competition at the Merkur Spiel-Arena.

While at the sitting volleyball match held during day five, the royals didn't hesitate to take a few pics with fans.

Harry was seen holding Meghan close as they watched on during the sitting volleyball competition.