A source told MailOnline: ‘Kylie was keeping a very low-profile at the party and headed to a private room behind a red curtain to celebrate with Timothee. It was the talk of the party!’

Deuxmoi also confirmed the sighting. Kylie attended the cinema screening as well as the afterparty, but was not pictured there.

EXCLUSIVE: Kylie Jenner made a secret trip to London to support boyfriend Timothee Chalamet at the Wonka party at the Royal Festival Hall on Tuesday

Timothee stars as a younger incarnation of the iconic Willy Wonka in the new movie – pictured ahead of the party which Kylie secretly attended

One fan tracked Kylie’s flight ahead of the big event and noted she was coming to London

Really? DeuxMoi confirmed that Kylie was at the party as a source confirmed the sighting to MailOnline

The reality star, 25, and the actor, 27, have been quietly dating since early April after celebrity gossip account DeuxMoi, after a tipster wrote in.

They said: ‘Anon pls!! Multiple sources have told me Timmy C has a new girl… Kylie Jenner.’

Kylie and Timothee are said to have sparked up a romance after they both attended the Jean-Paul Gaultier fashion show on January 25, 2023.

In mid-April, after news broke of their coupling, Kylie’s Range Rover was seen in Timothee’s driveway of his Beverly Hills home.

Her SUV drove straight up the Wonka star’s windy driveway, according to TMZ.

One day later, Timothee jumped into Kylie’s SUV after he attended an art show in Santa Monica, with her security guard jumping into his car and driving it, per TMZ.

They arrived at Tito’s Tacos in LA and her security team went and picked up food for them and brought it to the car.

That same month, People’s source reported that the stars were ‘hanging out and getting to know each other with another insider revealing that they ‘hang out every week’ but it’s ‘not serious.’

Coming soon: Wonka will be released in the UK on December 8, and the US on December 15

Timothee attended the premiere on Tuesday wearing a black Alexander McQueen suit with sparkling silver pinstripes.

He stars alongside Olivia Colman, who plays Mrs. Scrubbit and Hugh Grant, who plays an Oompa Loompa.

During an interview with Vogue in May, Timothée opened up about taking on the role of Wonka in the musical fantasy.

‘To work on something that will have an uncynical young audience, that was just a big joy,’ he explained to the outlet.

He added, ‘That’s why I was drawn to it. In a time and climate of intense political rhetoric, when there’s so much bad news all the time, this is hopefully going to be a piece of chocolate.’

The Little Women star also explained that his portrayal of Wonka would not be ‘cynical.’

‘This is a Willy that’s full of joy and hope and desire to become the greatest chocolatier,’ the star stated.

Timothee pictured at the aftrerparty with Rowan Atkinson and Sally Hawkins – Kylie attended but was not pictured there

Coming soon: Wonka is slated to officially release in the UK on December 8 just in time for Christmas – Timothee pictured at a photocall in London on Monday

Olivia Colman, Hugh Grant and Timothee were in high spirits despite the wet November weather as they attended Monday’s photocall