Wearing a pink off-the-shoulder evening gown, Katy accessorised with a matching clutch box and retro white sunglasses, while fiance Orlando wore a tuxedo for the black-tie event.
British star turned American late-night host James Corden and his wife Julia were also seen arriving at Villa Aurelia in Rome for the September wedding, with James throwing a wave to the cameras.
Karlie and her husband Joshua Kushner are also at the wedding.
Joshua is the brother of Ivanka Trumps husband Jared, and both Ivanka and Jared have also been pictured at the ceremony with Ivanka wearing a peach Grecian-inspired gown.
Princess Beatrice and Princess Eugenie will also be watching the nuptials.
Beatrice was pictured earlier in the day with Misha entering the 17th-century villa which has been the property of the American Academy in Rome since 1909.
Misha and Meghan have been pals for many years, and recently joined forces on a capsule clothing collection benefiting Smart Works, which focuses its efforts on providing unemployed women clothing for job interviews.
Meghan said the wardrobe – made up of five items – was a special pRead More – Source