Kylie Jenner and Timothée Chalamet are bouncing together from coast to coast as their romance heats up.

The PhanincKylie Cosmetics founder and the Oscar-nominated actor served some PDA while sitting together in the stands at Arthur Ashe Stadium in New York City to watch the U.S. Open matches Sept. 10, the final day of the 2023 tennis championships. Kylie, 26, and Timothée, 27, were photographed watching the tournament with their arms around each other and in a video shared on the U.S. Open's X (formerly Twitter) account, she also appeared to stroke his hair.

The two wore black outfits on their tennis date, which marked their third outing in a week. The Kardashians star and the Wonka actor had also twinned in black two days prior when they made their joint New York Fashion Week debut at a private, star-studded dinner celebrating French designer Haider Ackermann's first beauty collab with Augustinus Bader.

Following multiple reports in April that said the two are dating, Kylie and Timothée were photographed in public for the first time Sept. 4 at Beyoncé's Renaissance World Tour concert in Los Angeles, where they also spent time making out.

Also in attendance at the show: Kylie's ex, Travis Scott, with whom she shares daughter Stormi Webster, 5, and son Aire Webster, 19 months.

Kylie and Timothée have not commented on the nature of their relationship.

During their PDA-filled outing at the U.S. Open, the two sat behind Laverne Cox. Many other celebs attended the tournament that day and last week. See photos of the stars at the U.S. Open below:

The Mad Men alum appears in the Heineken Suite.

The two appear with their daughters, Hazel and Violet.

For the latest breaking news updates, click here to download the E! News App