James Harden and Khloe Kardashian are starting to do thing that couples do - like go to functions involving the other person.

First, it was Harden, the 25-year-old Houston Rockets star, who accompanied Khloe to sister Kylie Jenner's 18th birthday bash, Hollywoodlife.com reported.

James Harden, Khloe Kardashian still together despite cheating claims against Harden

"During the night, Khloe rocked a hot velvet number with mesh stripes, flaunting off her toned and tanned body. She added a pair of classic Louboutin heels and wore a rock star shade of blue eye shadow. James dressed casual, wearing a pair of fashionable ripped jeans and a long-sleeved shirt. Though their outfits were radically different, they seemed to match together at the end of the night: the two reportedly left the birthday bash in the same car!

"This isn't the first Kardashian-Jenner event that James has attended. He was seen in a snapchat video taken at Kylie's High School graduation party. With James becoming a fixture at family events, does this mean the rumored relationship between him and Khloe is getting serious?"

Khloe Kardashian grills James Harden over allegations of an affair with Australian student Rochelle Relf.

A day later, it was the 31-year-old Kardashian sitting courtside as Harden played in a Drew League playoff game at King Drew Magnet High School in the Compton area of Los Angeles, E! Online reported.

"Khloé sported a cleavage-baring back top and matching pants, paired with a bright coral floral jacket and sunglasses as she sat courtside," E! reported. "Harden scored 25 points to help LAUNFD beat the Citi Team Blazers 83-72.

The two have been an item since June when they had a secret rendezvous in Hawaii. Harden was rumored to have an affair with an Australian student in Sydney after his romance with Kardashian, but the couple reportedly talked it out, and apparently, Kardashian trusted what Harden told her.