Gwyneth Paltrow and Leonardo DiCaprio join Katy Perry as they mingle with designer Diane Von Furstenberg at a garden party

Leonardo DiCaprio and Gwyneth Paltrow kept it casual as they feted a fashion icon over the weekend. 

The Oscar winners were among the Hollywood elite who celebrated the birthday of British Vogue Contributing Editor Nona Summers at a party thrown by fashion superstar Diane Von Furstenberg, 77.

Paltrow, 51, looked sleek in a brown belted shirtdress with double pockets.

The Goop founder showcased her shapely legs via a front slit in the frock and wore a pair of sage green walking sandals.

The Avengers: Endgame star's long, blonde hair was styled straight and she wore natural looking makeup. 

Paltrow, 51, looked sleek in a brown belted shirtdress with double pockets as she attended a party hosted by designer Diane Von Furstenberg, 77, over the weekend. The designer put on a colorful display in blue, yellow and pink floral print pants and top

Von Furstenberg put on a colorful display in blue, yellow and pink floral print pants and top. 

The designer wore a black camisole and accessorized with a necklace featuring a series of gold medallions and multi-toned flat mules.

Her dark hair was styled in natural waves and she wore natural looking makeup. 

'Saturday before Oscar’s…A lovely day, lovely garden… lovely friends … ❤️❤️,' Von Furstenberg penned next to a series of snaps from the event.  

DiCaprio, 49, looked relaxed in a gray T-shirt and bill cap with sunglasses as he posed with his hostess and Vogue executive Edward Enniful. 

The Revenant star wore a closely trimmed beard and mustache and dark sunglasses. 

Ava Duvernay, 51, streamlined her look, wearing a black cable knit sweater.

The Origin director's long, dark hair was styled in thin braids and pulled back into a ponytail. 

Leonardo DiCaprio, 49, looked relaxed in a gray T-shirt and bill cap with sunglasses as he posed with his hostess and Vogue executive Edward Enniful.

Katy Perry, 39, kept her look low-key, wearing a white tank top with a black bra. The Firework singer wore makeup that accentuated her bright blue eyes and added a pop of color with bright pink lipstick

Diane also shared this photo of Katy sitting next to Sam Altman, an American entrepreneur and investor best known as the CEO of OpenAI since 2019. Altman is considered to be one of the leading figures of the AI boom

Ava Duvernay, 51, streamlined her look, wearing a black cable knit sweater. She posed for a party photo with Von Furstenberg, and fellow guest, professor Anita Hill, who looked elegant in a cream top and black jacket

British Vogue Contributing Editor Nona Summers was the guest of honor

She posed for a party photo with Von Furstenberg, and fellow guest, professor Anita Hill, who looked elegant in a cream top and black jacket. 

The Drum Major for Justice Award winner accessorized with a long gold chain, hoop earrings and large sunglasses. 

Nicki Hilton, 40, showcased her fit form in a brown and white dotted sundress. Cutouts at the waist at the waist were trimmed in a complementary blue and white material.

The heiress' long, blonde hair was styled in a high half-ponytail with long layers.

Nicki Hilton, 40, showcased her fit form in a brown and white dotted sundress. Cutouts at the waist at the waist were trimmed in a complementary blue and white material. The heiress' long, blonde hair was styled in a high half-ponytail with long layers

She carried a green shoulder bag and wore sunglasses with a clear, square frame. 

Katy Perry, 39, kept her look low-key, wearing a white tank top with a black bra.

The Firework singer wore makeup that accentuated her bright blue eyes and added a pop of color with bright pink lipstick. 

Decorations for the garden party included picnic tables decorated with floral runners and multi-toned poppies and other blossoms

Large pillows and blankets were laid around the lawn, perfect for lounging in the late winter sun

The Billboard Music Award winner's long, black hair was styled straight and she accessorized with thick gold hoop earrings. 

The California Gurls hitmaker sported a gel manicure with light pink nail polish. 

Decorations for the garden party included picnic tables decorated with floral runners and multi-toned poppies and other blossoms. 

Bamboo settees and chairs were placed around the garden. Large pillows and blankets were laid around the lawn, perfect for lounging in the late winter sun.