Celeb Spotter 077: Chrissy Teigen and Reese Witherspoon start book tours, models hit Milan Fashion Week

Fashion month continues!

Gigi and Bella Hadid, Kendall Jenner, Kaia Gerber and more of the world's top models jetted off to Italy this week for Milan Fashion Week, during which they were all photographed stepping out together on various occasions.

Back in the Big Apple, Chrissy Teigen celebrated the release of her second cookbook, "Cravings: Hungry For More," with a slew of appearances, while Reese Witherspoon also kicked off her "Whiskey in a Teacup" book tour.

Ariana Grande made her first public outing since ex Mac Miller's shocking overdose, Carrie Underwood debuted her baby bump and Hailey Baldwin watched along as fiancé Justin Bieber delivered an impromptu performance outside of Buckingham Palace.

See the best celebrity sightings of the week below: