Nicky, 34, celebrated with Paris, 36, mom Kathy Hilton and other family and friends Tuesday after announcing she's pregnant and expecting her second child with husband James Rothschild.
Nicky and Paris wore coordinating outfits, with the expectant mom in a blue, pink and green patterned minidress and Paris in a pink dress and cardigan. Nicky posted several photos from the fête on Twitter.
"Thank you @ParisHilton for throwing the sweetest tea for the mama to be," she captioned the pictures.
Paris also shared snapshots from the bash, including a group photo with Nicky, Kathy, Real Housewives stars Bethenny Frankel and Kyle Richards, and other guests.
"Celebrating the new baby with the #Squad. #NickysBabyShower," she wrote.
Nicky already shares 16-month-old daughter Lily Grace with Rothschild, whom she married in 2015. he star's rep confirmed to Us Weekly in July that Nicky and Rothschild are expecting another child.
"The couple are thrilled about the new addition to their family," the rep said.