Congratulatory phone calls are so last decade.

After Kristin Cavallari gave birth to son Camden Jack Wednesday -- her first child with fiance Jay Cutler -- her former Hills costars took to Twitter to send well wishes to the new mom.

"Congrats!!!!!" Audrina Patridge wrote. "Can't wait to see Camden. So happy for you!"

PHOTOS: Kristin's pregnancy style

"Congratulations on your new baby boy!" tweeted Heidi Montag. "One of life's greatest gifts! Enjoy mama! Oxxo."

"Congratulations on Camden's birth!" Heidi's husband, Spencer Pratt, wrote. "I'm free to be the Godfather if you need one!"

PHOTOS: Biggest Hills moments ever

Cavallari herself, 25, turned to the social networking site Wednesday morning to officially announce the birth of her son.

"We are thrilled to welcome Camden Jack Cutler into the world," the former MTV star wrote. "He was born this morning weighing 7 lbs, 9 oz. Everyone is doing great!"

This article originally appeared on Kristin Cavallari Gives Birth to Son Camden: Hills Stars Send Congrats!