“Cheers! I have one of Gunner’s godmothers here, Jen Bunney,” Montag, 31, said in a video on her Instagram Story Thursday, which she captioned: “Celebrating @gunnerpratt with one of his godmother’s @jennifer_nora737.”
“We’re celebrating Gunner,” Bunney, 31, said, adding, “He’s the best baby ever. We love him so much. “
Montag and Pratt, who wed in November 2008, welcomed their first child on Oct. 1.
Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Babies newsletter.
Fans came to know Bunney in 2004 as Lauren Conrad‘s childhood friend who made cameos on MTV’s Laguna Beach and The Hills, during which Bunney and Montag first filmed together in 2007.
In August 2014, Montag and Pratt attended Bunney’s wedding to husband Taylor Dunphy at the Trump National Golf Club in Palos Verdes, Calif.