Nina Agdal and Jack Brinkley-Cook Split After 4 Years Together: Source

Nina Agdal and Jack Brinkley-Cook have called it quits after four years of dating, a source confirms to PEOPLE.

As first reported by Page Six, the 29-year-old model and the 26-year-old son of Christie Brinkley and real estate developer Richard Taubman have unfollowed each other on Instagram. The former couple also deleted pictures of each other from their accounts.

Adgal and Brinkley-Cook's reps did not immediately respond to PEOPLE's request for comment.

They were last spotted together on a boat ride in October, after celebrating their four-year anniversary in June.

Last year, the model posted a series of Instagram photos with Brinkley-Cook for their three-year anniversary.

"3 years later. Still on a beach. Still drinking wine. Still cracking jokes no one else would find funny ❤️" Sports Illustrated model captioned the post.

Agdal — who previously dated Leonardo DiCaprio — and Brinkley-Cook were first spotted out together in New York City during the summer of 2017.

Brinkley-Cook rarely posts on social media, but Agdal shared several photos and videos of the couple on her Instagram account over the years.

In 2018, the model opened up about her relationship with Christie Brinkley during an appearance on Watch What Happens Live with Andy Cohen.

"It's actually really, really good. Me and Christie are super cool," Agdal explained. "She's one of the most, you know, the smartest woman and one of the most beautiful women. I like get surprised, I walk out of the door in the Hamptons at 10 a.m. and she looks 10 times better than I do at all times. She's an incredible woman. She's so sweet."

She told PEOPLE in 2019, "If I have a question regarding my career or regarding something I'm doing, I'll ask her," adding, "[Brinkley] is kind of just family. We talk about family stuff and real life things. Not so much about modeling."