Richie – looking fit and fab in a short black dress – and the Good Charlotte frontman headed to a star-studded dinner in honor of designer Charlotte Ronson at the Hollywood Roosevelt Hotel's Dakota Restaurant.
And the proud papa couldn't help boasting about his three-month-old bundle of joy. "It's been so crazy," he told the VIP table, where fellow guests included Lindsay Lohan and her constant companion, DJ Samantha Ronson. "Man, but it's great."
Richie's fuller figure was also a hot topic of conversation.
"You're such a pretty mommy," said one friend, party promoter Ashlee Margolis. "And your boobs are way better than mine." (The two then posed together for a picture before Richie showed off shots of Harlow on her digital camera.)
Later, the group tucked into dinner with gusto, downing Petit Filet steaks, creamed spinach with bacon and sides of fries.
Lohan – wearing a Charlotte Ronson top – seemed rather reserved during the party, text messaging frequently on her BlackBerry. Ronson, meanwhile, was more outgoing, chatting easily with the fellow guests.