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Milestones with the Maliks! Gigi Hadid spent her 21st birthday with her own family and that of her boyfriend's family.

The model turned 21 on Saturday and she and boyfriend Zayn Malik took to social media to document their fun with their families in Malibu Calif.

The former One Directioner shared several sweet snaps to Instagram from the weekend on Monday, including one with his mom and sisters on the beach. "Chillin with the fam," the shirtless singer captioned the snap.

He posted another one, as well, but this one is of Gigi and her model sister Bella Hadid hiking up beach.

Gigi shared her own gorgeous photo from her idyllic weekend, which appears to show Bella walking off into the distance on a coastal path.

The weekend's significance wasn't lost on Bella, who shared several snaps dedicated to her sister's big day.

"Happy birthday to my best friend (heart emoji) Thank you for being you and making me laugh til I cry. You have grown into the most incredible, kind, generous, loving, beautiful big sister I could ever ask for," she wrote of a photo of her and Gigi. "You are my squishy cheeks!!!! I love you very much. also you're still only 5. HAPPY 21 !!!! @gigihadid."

She later shared a pic of her in a swimsuit that said "Gigi." In the snap, Bella points to the name while captioning the photo: "#1 Fan."

Really, Gigi's No. 1 fan may be Zayn, though. The couple has been inseparable since they began dating last November.

Earlier this month the couple steamed up the pages of Vogue magazine, posing for multiple shots, many of them incredibly romantic.

Both Gigi and Zayn posted several of the images on their own Instagrams, though neither of them elaborated on the snaps.

Gigi shared an image of the couple in bed. A bearded Zayn lays down while she does a hand stand. The two smile as they appear to be on the verge of kissing. Zayn shared the same image.

Another image shows Zayn and Gigi caressing each other on a balcony overlooking the romantic city. In the shot, Gigi wears a burgundy and black Victoria Beckham midi dress with matching Jimmy Choo heels, while the former One Direction singer looks dapper in head-to-toe Saint Laurent by Hedi Slimane.

"That's amore," Vogue said in an Instagram post of the snap. "@gigihadid shows off spring's finest plaids with @zayn in Naples."