updated 05/28/2013 AT 2:00 PM ET
•originally published 05/28/2013 AT 3:05 PM ET
It was a pretty cool night for a 5-year-old.
Grant Holmquist, – the blue-eyed, chubby-cheeked Hangover baby who reprises his role of Tyler (a.k.a. Carlos) in The Hangover Part III – got to walk the red carpet with his costars in Hollywood last week. And it seems that they’re just as taken with the little guy as moviegoers.
On set, “Zach [Galifianakis] did an amazing job loosening Grant up,” the little actor’s mom, Carrie Holmquist (who was on hand to snap photos), told PEOPLE. And Grant was clearly delighted to see “Zachy,” as he calls him, on the red carpet for the premiere. (Grant only walked the carpet, he wasn’t allowed at the R-rated screening since he’s a minor.)
In addition to Galifianakis, Bradley Cooper (who endearingly got down on Grant’s level at the premiere) and Ed Helms also made their young costar feel most welcome while filming, Carrie added.
“There were toys all over the place and they were pretending a stuffed dog was attacking them,” she says. “They were throwing it back and forth, just making Grant laugh.”