Mandy Moore Shares Adorable Photo of Son Gus 'Relishing His Role as Big Bro' to Baby Ozzie

Mandy Moore/instagram

Mandy Moore's son Gus is loving his new role as a big brother!

On Wednesday, the This Is Us star, 38, shared a heartwarming picture of Gus, 20 months, holding his new baby brother Ozzie in his lap, beaming with a huge smile as he looks lovingly at the infant.

Moore and husband Taylor Goldsmith smile alongside Gus as they help the toddler hold little Ozzie, who is swaddled comfortably in a blanket. The couple announced the arrival of baby Ozzie in a joint post on Instagram last week.

"Gus relishing his role as Big Bro 😎," Moore captioned the adorable sibling photo on Instagram.

Many of Moore's famous friends couldn't get over the cuteness of the picture, dropping comments on the post about the sweet moment.

"Heaven wow!" wrote Julianne Hough, while Matthew Koma added, "Buddies."

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Dave Annable replied, "The sweetest. ☺️❤️"

"Ozzie is here!" wrote Moore in the sweet birth announcement on Friday, which featured a carousel of black-and-white photos from the hospital.

"Oscar Bennett Goldsmith arrived a little late but with much aplomb (and an easier/speedier delivery than his big brother, much to the delight of his parents)," she continued in the caption. "Every adage is true: our hearts have doubled in size and the immediacy of the love is astounding. He is beyond words and we are so grateful for our family of four! 💓💓💓💓."

While Gus is already proving to be a great big brother, Moore told PEOPLE last month that the toddler was "entirely unaware" he was about to get a sibling.

"I say baby brother all the time and point to my stomach, and he'll say, 'Baby brother,' but he has no idea what's going on," she said with a laugh. "His level of awareness of the world is just starting to kick in which maybe is for the best because we won't have to deal with the innate jealousy that sometimes comes along with bringing a new sibling into the world."

"We'll figure out how to best introduce the two of them, but yeah, he has no idea what's about to hit him," she added.