Kaia Gerber and Lewis Pullman made a determined effort to keep their romance "under wraps"

A source told Us Weekly: "Kaia and Lewis have actually been together for a while now.

"They started dating in early December. They kept it under wraps until the news of her and Austin's split came out. Kaia and Austin have been broken up since October."

Kaia and Lewis enjoyed a series of dates around Los Angeles in December, but the brunette beauty - who is the daughter of model Cindy Crawford and business tycoon Rande Gerber - has tried to keep a low profile in recent weeks.

The insider explained: "In early December, Kaia and Lewis started seriously hanging out and were seen all around Los Angeles, but mostly on the east side.

"Kaia would make sure to be in a hat to try and be unnoticed, but they would be at their favourite restaurants, bars and clubs, holding hands and showing PDA. They were just frequenting crowds that didn't really know them."

Kaia and Lewis' relationship has been "very natural and relaxed" so far.

The runway star - who has previously dated comedian Pete Davidson and actor Jacob Elordi - likes that their romance is more low-key than her previous relationships.

The source added: "They run in the same circle and have similar friend groups, and that's how they were introduced.

"Kaia likes that this relationship feels low-pressure and that Lewis is a very low-key guy."