"Love! This! Bag! #Luckiest #pharellxchanel," she captioned the pictures.
Patrick, 54, and Pia made their public debut at a Halloween party in Los Angeles last week. They also attend the Premiere of FOX's Ford v Ferrari at the Chinese Theatre in Hollywood on Monday evening.
While this was only the couple’s second public appearance, Pia has been secretly dating Patrick – who is finalising his divorce from wife Lauren Sanchez – since May. In June, she posted on Instagram about their trip to Paris, with Pia declaring she was “in love”.
Patrick finalised his divorce from Lauren Sanchez in mid-October after her affair with Amazon's billionaire boss Jeff Bezos was unveiled. They were married for 13 years.
They will share joint physical custody of their two children, a son and a daughter.
Jeff split and his wife MacKenzie first announced their separation in January.
After finalizing their divorce, MacKenzie will keep a $50 billion stake in her ex-husband’s company. It makes her the 23rd richest person in the world.