The reality star, 26, looked radiant as she flashed the diamond sparkler while cradling the brown dachshund who she called Moo Pants – sparking speculation the ring could be from the Oscar nominee, 27.
Kylie showed off her flawless make-up in the video, wearing smoky shadow, rosy blush, mascara and lashings of lipgloss.
Her raven locks were styled in soft waves and worn down across her shoulders.
The star also showed her new dog lying on her bed as she gushed: ‘You’re so cute.’
Jenner and Chalamet – whose mutual friend is designer Haider Ackermann – were last pictured together at the WSJ. Magazine 2023 Innovator Awards at MoMA in Manhattan on November 1.
There have been unconfirmed reports that the Entergalactic actor and The Kardashians producer-star met as far back as 2019 at Nobu Malibu before ringing in the New Year in Aspen.
Timothée previously romanced his The King leading lady Lily-Rose Depp, Extrapolations actress Eiza González, and Madonna’s eldest Lourdes Leon.
Kylie has two children – daughter Stormi, 5; and son Aire, 21 months – from her on/off five-year relationship with disgraced Astroworld founder Travis Scott, which ended in December.
Chalamet beat out Tom Holland to play the younger Willy Wonka in Paul King’s Charlie and the Chocolate Factory musical prequel Wonka, which hits UK theaters December 8 and US theaters December 15.
The $125M-budget Roald Dahl big-screen adaptation also features Olivia Colman, Hugh Grant, Sally Hawkins, Rowan Atkinson, Keegan-Michael Key, and Matt Lucas.
The Bones and All producer-star will also reprise his role as Duke-turned-Fremen Paul Atreides in Denis Villeneuve’s sequel Dune: Part Two, which hits US/UK theaters on March 15.
The ensemble also features Zendaya, Rebecca Ferguson, Josh Brolin, Stellan Skarsgård, Dave Bautista, Stephen McKinley Henderson, Charlotte Rampling, Javier Bardem, Florence Pugh, Austin Butler, Léa Seydoux, and Christopher Walken.
The Canadian 56-year-old filmmaker’s critically-acclaimed first installment – based on Frank Herbert’s 1965 sci-fi novel – amassed $402M at the global box office in 2021.