Many members of the Hilton clan stepped out to celebrate Milou’s big day

milou hilton birthday party

Milou Hilton birthday party. PHOTO: MARK VON HOLDEN

Tessa and Barron Hilton’s daughter Milou is celebrating a big birthday!

Over the weekend, Barron’s parents Kathy and Rick Hilton hosted a birthday party for their granddaughter Milou at their home in Bel Air as the little girl turned 4.

The unicorn-themed party was attended by many members of the Hilton family, including Paris Hilton, her husband Carter Reum and their son Phoenix, as well as Kyle Richards, and many others.

In exclusive photos shared with PEOPLE from the event, Milou can be seen getting ready to eat her unicorn birthday cake, sitting on the table next to her dad Barron, 34. The proud dad holds the couple’s son Caspian, 17 months, and stands next to wife Tessa, who is currently pregnant with the couple’s third child.

milou hilton birthday party

Milou Hilton birthday party.MARK VON HOLDEN

On either side of the family of four, Kathy and Rick stand smiling as the cake is cut. The soiree included pony rides, bounce houses and an arts and crafts station. Guests left with personalized unicorn Printfresh pajamas, Lolli & Pop macaroons and Bulgari Fragrance baby gifts.

In another photo from the party, Milou kisses her mom’s nose as they stand in front of a pink and purple butterfly arch done by OC Balloon Bar. The family of four also poses together on the lawn, with Milou donning a fairy costume for her special day.

milou hilton birthday party

Milou Hilton’s birthday cake.MARK VON HOLDEN

Milou’s aunt Paris was also at the event, pictured sitting in a white bouncy castle with Reum and their son Phoenix. Paris was later photographed sitting next to her aunt Kathy.

In September, Tessa shared a pair of family beach photos on Instagram, revealing her bump and the couple’s exciting baby news.

“Our third little angel is on its way!! 👼🏼🍼🤰🏼💙,” she captioned the shot.

Earlier that month, she shared a sweet tribute to her son on Instagram in celebration of his first birthday.

milou hilton birthday party

Milou Hilton birthday party.MARK VON HOLDEN

“Happy 1st Birthday to our darling, smiley, sweetest, most loving and enchanting little prince, Caspian. I am so lucky you chose me to be your mother 💙.”

Later that winter, Tessa took her two kids to New York City, along with sister-in-law Nicky Hilton and her two daughters Theodora “Teddy” Marilyn, 4, and Lily-Grace Victoria, 6.

Tessa shared a few photos of their adventures on her Instagram Story, which included Barron ice skating in Central Park with one of their kids.

milou hilton birthday party

Milou Hilton birthday party.MARK VON HOLDEN

There was also a giant ice cream sundae to celebrate Nicky’s daughter Teddy on her 6th birthday, and later, Tessa and Nicky brought their kids to see the Rockettes at the Radio City Music Hall, which happened to be Tessa’s son Caspian’s first time.

Nicky and Tessa’s daughters posed together outside of the venue, wearing adorable dresses for the special day.