Caring heiresses! Pregnant Nicky Hilton and Kate Mara look beautiful in blue as they support Humane Society gala together in New York

They both come from very, very rich families.

And Nicky Hilton and Kate Mara put some of those dollars to good work as they attended the Humane Society's To The Rescue Gala in New York on Friday night.

Pregnant Nicky's wore a resplendent blue and silver bejeweled gown, cinched and the waist by glittering gold belt.

Caring heiresses! Nicky Hilton and Kate Mara both looked beautiful in blue as they supported the Humane Society's To The Rescue Gala in New York on Friday night
Caring heiresses! Nicky Hilton and Kate Mara both looked beautiful in blue as they supported the Humane Society's To The Rescue Gala in New York on Friday night

Caring heiresses! Nicky Hilton and Kate Mara both looked beautiful in blue as they supported the Humane Society's To The Rescue Gala in New York on Friday night

Coupled with her perfectly rotund belly — and sky high net worth — she closely resembled a walking Fabergé Egg.

Kate matched her blue, opting for a dark velour two-piece suit.

She paired it with short open-toe gold heels, and a cute pink pox purse.  

Magnificent: Pregnant Nicky's wore a resplendent blue and silver bejeweled gown, cinched and the waist by glittering gold belt

Magnificent: Pregnant Nicky's wore a resplendent blue and silver bejeweled gown, cinched and the waist by glittering gold belt

Treasure inside: Coupled with her perfectly rotund belly ¿ and sky high net worth ¿ she closely resembled a walking Fabergé Egg
Treasure inside: Coupled with her perfectly rotund belly ¿ and sky high net worth ¿ she closely resembled a walking Fabergé Egg

Treasure inside: Coupled with her perfectly rotund belly — and sky high net worth — she closely resembled a walking Fabergé Egg

Cute: Kate matched her blue, opting for a dark velour two-piece suit

Cute: Kate matched her blue, opting for a dark velour two-piece suit

The gala was honoring Matchbox Twenty frontman Rob Thomas and his wife Marisol, and the charity they set up.

Sidewalk Angels Foundation is dedicated to providing critically needed funds and support to more than 20 no-kill animal shelters and rescues across the US, and in the Caribbean.

There were plenty of other mega-rich families represented besides, including Ralph Lauren's daughter Dylan, and Michael Bloomberg's daughter Georgina, William Randolph Hearst's great-granddaughter Amanda, and John D Rockefeller's great-great-granddaughter Ariana. 

Loaded: There were plenty of other mega-rich families represented besides, including Michael Bloomberg's daughter Georgina (L) and Ralph Lauren's daughter Dylan
Loaded: There were plenty of other mega-rich families represented besides, including Michael Bloomberg's daughter Georgina (L) and Ralph Lauren's daughter Dylan

Loaded: There were plenty of other mega-rich families represented besides, including Michael Bloomberg's daughter Georgina (L) and Ralph Lauren's daughter Dylan

Sidewalk Angels: The gala was honoring Matchbox Twenty frontman Rob Thomas and his wife Marisol, and the charity they set up

Sidewalk Angels: The gala was honoring Matchbox Twenty frontman Rob Thomas and his wife Marisol, and the charity they set up

Old money: Oil tycoon John D Rockefeller's great-great-granddaughter Ariana (L) and Media magnate William Randolph Hearst's great-granddaughter Amanda were there too
Old money: Oil tycoon John D Rockefeller's great-great-granddaughter Ariana (L) and Media magnate William Randolph Hearst's great-granddaughter Amanda were there too

Old money: Oil tycoon John D Rockefeller's great-great-granddaughter Ariana (L) and Media magnate William Randolph Hearst's great-granddaughter Amanda were there too

Other guests supporting the night included Malin Akerman who looked gorgeous in a black and white halterneck jumpsuit.

She arrived with her new fiance Jack Donnelly, having only announced their engagement exactly four weeks earlier.

Photographer and Next Top Model judge Nigel Barker looked dashing in a white tux, while his wife Cristen put on a sexy display in a semi sheer black dress.

Engagement: Malik Akerman, who arrived with her new fiance Jack Donnelly, looked gorgeous in a black and white halterneck jumpsuit

Engagement: Malik Akerman, who arrived with her new fiance Jack Donnelly, looked gorgeous in a black and white halterneck jumpsuit

Smize: Photographer and Next Top Model judge Nigel Barker looked dashing in a white tux, while his wife Cristen put on a sexy display in a semi sheer black dress

Smize: Photographer and Next Top Model judge Nigel Barker looked dashing in a white tux, while his wife Cristen put on a sexy display in a semi sheer black dress