Tristan Thompson and Kylie Jenner.

Khloe Kardashian has responded to claims Tristan Thompson cheated on her with her sister Kylie Jenner's best friend Jordyn Woods.

The basketball star reportedly hooked up with 21-year-old Jordyn at a house party on Sunday night, according to TMZ.

"Tristan and Jordyn were all over each other making out," an insider told the site.

Kylie Jenner and best friend Jordyn Woods.

"Everyone was just hanging out, smoking hookah and drinking when they were instructed to stop all use of cell phones or leave. It’s not unusual for phones to be confiscated while at the party with high-profile people.

However, the vibe was chill and nobody was really checking for security until later in the night.

"Once partygoers put their phones away, Kylie Jenner's best friend Jordyn Woods arrived to the late-night kickback. Thompson and Woods were all over each other, and, it wasn’t just "friendly." They couldn’t keep their hands off of each other.'

The source added: 'When partygoers asked to use their phone, they were told that they may as well leave if they needed to do so as Jordyn wouldn’t be leaving anytime soon.

Jordyn didn’t leave the party until the early hours of 7 a.m."

Following the allegations, Instagram site Hollywood Unlocked revealed that a contributor was at the house party and saw what went down.

Instagram post by Hollywood unlocked

Khloe then 'liked' the post and responded with multiple emoji's of a person yelling.While her best friend Malika replied 'STRONG FACTS.'

Tristan also appeared to respond to the allegations by tweeting 'FAKE NEWS' - though he later deleted the post.

Khloe and Tristan share 10-month-old baby daughter True Thompson.

Khloe and her daughter True Thompson.

According to TMZ, Khloe has told the basketball star they are over for good this time.

During Khloe's pregnancy rumours were rife that Tristan had cheated with multiple women.

After multiple pictures and videos emerged of Tristan, Khloe ultimately decided to forgive him with insiders saying she was desperate to keep her family together.

On Valentine's Day, Khloe sparked concern when she shared multiple posts about being broken-hearted.

The couple had spent the romantic holiday apart, with Khloe in Los Angeles with her family while Tristan remained in Ohio playing for the Cleveland Cavaliers.

However, Tristan made sure Khloe was still treated as he sent her a giant bouquet of flowers in the shape of a love heart.