She’s his “Lady Bird.”

Kylie Jenner and Timothée Chalamet are reportedly keeping their relationship “fun” and “casual” for now.

“It’s not serious,” a source told “Entertainment Tonight” Monday, “but Kylie is enjoying hanging out with Timothée and seeing where it goes.”

The insider noted that the “Call Me by Your Name” actor, 27, is unlike anyone the “Kardashians” star, 25, has previously dated.

“It’s been really fun for her because it feels a lot different than her past relationships,” the source explained. “It’s new and exciting for Kylie, and she’s having a lot of fun.”

Kylie Jenner’s relationship with Timothée Chalamet is reportedly only “casual.” Instagram

“It’s not serious, but Kylie is enjoying hanging out with Timothée and seeing where it goes,” a source shared. WireImage

That said, Jenner reportedly wants to keep things on the down-low, which explains why she attended the 2023 Coachella music festival this weekend sans Chalamet.

“Kylie decided she didn’t want to make things public with Timothée this past weekend at Coachella and really just wanted to chill and have fun with her friends,” the source shared.

As for how the unlikely pair were introduced, the insider speculated that the makeup mogul’s sister Kendall Jenner played a part.

Jenner apparently doesn’t want to make things public with the actor just yet. kyliejenner/Instagram

“Timothée is also friends with Kendall, so it’s been easy for Kylie to integrate him into her life,” the source said.

Rumors started swirling that Kylie and Chalamet were an item in early April after sources told gossip Instagram account Deuxmoi that they were seeing each other, with one tipster claiming the romance has been going on as far back as January, when the pair was seen interacting at Paris Fashion Week.

The chatter became all the more real when Kylie’s car was spotted parked outside Chalamet’s Beverly Hills mansion last week. And the next day, they enjoyed a taco date.

Relationship rumors for the duo started circulating at the beginning of this month. Getty Images

A source told Us Weekly at the time that the “Keeping Up With the Kardashians” alum was “enjoying getting to know” the Oscar nominee and was “open to seeing where things go.”

“Timothée is a total gentleman and treats [Kylie] with respect,” the insider said, adding that Chalamet “makes her laugh.”

The source explained that the stars have only hung out a couple of times and that their fling was “very new” but that they have “really good chemistry.”

Jenner’s car was recently seen outside the “Dune” star’s home. Instagram/Kylie Jenner

Despite multiple reports of their romance, neither party has confirmed they are seeing each other, and they have yet to actually be photographed together.

Reps for Kylie and Chalamet did not immediately respond to Page Six’s requests for comment.

The Kylie Cosmetics founder’s relationship with the “Dune” star comes on the heels of her breakup from longtime partner Travis Scott.

Jenner and Travis Scott broke up last winter. Getty Images for The Recording A

She and Scott share two kids. kyliejenner/Instagram

She and Scott — who share 5-year-old daughter Stormi and 1-year-old son Aire — broke up for the second time around December 2022 when they spent the holidays separately.

“They have split several times in the past, and this is probably not the end of their relationship,” an insider told People at the time.

The “Sicko Mode” rapper, 31, was hit with cheating allegations prior to the breakup, though he denied the claims.

Kylie and Scott, who started dating in April 2017,  welcomed their daughter in February 2018. They then briefly broke up in October 2019 but continued to co-parent and were back together by May 2021.

She and the rapper had dated on and off since 2017. Xavier Collin/Image Press Agency/MEGA

Chalamet has reportedly been romantically involved with Lourdes Leon, Lily-Rose Depp, and Eiza González. Getty Images

That summer, Page Six revealed that the now-exes were expecting their second child, and they welcomed Aire in February 2022.

While the Lip Kit queen appears to be moving on from the rapper with Chalamet, he has seemingly continued to lust over her and even left a thirsty comment on one of her Instagram photos after their split.

Meanwhile, Chalamet has been romantically linked to a number of beauties, including Lourdes Leon, Lily-Rose Depp and Eiza González.