Mandy Moore celebrates Justin Hartley's birthday: 'It’s an honor to be your TV mom'

Justin Hartley's "This is Us" co-stars showered him with love on his 44th birthday Friday.

Chrissy Metz, who plays Hartley's sister on the hit NBC drama, kicked off the festivities by sharing a gallery of photos of the pair together.

"THIS GUY has a birthday today!" Metz wrote in the caption. "Wishing you the happiest day and a beautiful year full of light, love, health, and laughter. Love you, bruv! 🎈🎉❤️"

Mandy Moore, who plays Hartley's mom, shared her own gallery of pics of the show's stars, gushing, "Happy Birthday to one of the greats. To know you is to love you, @justinhartley."

"It’s really not fair that someone can be as talented, handsome, hilarious and generous as you but alas ... here we are," Moore continued. "It’s an honor to be your TV mom. Can’t wait to celebrate and toast you in person one of these days!"

Susan Kelechi Watson, who plays Hartley's sister-in-law, helped Hartley celebrate by toasting him with an adult beverage.

"Happiest Birthday to this amazing guy @justinhartley ! Having a shot of @RevelSpirits in your honor today Jus," she wrote next to a pic of the pair embracing.

Hartley also got a birthday shoutout from the official "This is Us" Twitter page. which shared several videos of Hartley on the drama — including many of him showing off his buff physique.

"It's @justinhartley's birthday, but somehow we're the ones getting a present," wrote the show.