In a sneak peek clip from an all-new episode of Keeping Up With the Kardashians, the 35-year-old reality star reveals the news to two of her sisters, Kourtney Kardashian and Kendall Jenner.
"I've been doing hormone injections for about five days and the injection process has been fine," Khloe explains. "I don't know why, I'm like, 'Oh, OK, it's not that bad.'"
"I do have a sperm donor," Khloe says, as her sisters ask who he is and if they can see a photo. "Yeah, Tristan."
In a solo interview, Khloe then says that while the process would be easier and probably "the smarter choice," it's also a bit "weird" since she and Tristan, whom she shares 2-year-old daughter True with, are no longer together.
"He has to sign, like, legal paperwork that he would just be my sperm donor," Khloe tells Kendall and Kourtney. "But you never know. What if, in three years, I get married to someone and I'm like, 'You know what, I don't want that.'"
Khloe first joked about Tristan being a sperm donor in last week's episode, which showcased a semi-awkward chat with the NBA star.
During a FaceTime call, while the pair were sifting through which of True's toys to get rid of, Tristan said, "What happens if we have another girl? We'll have to buy it all over again."
When a confused Khloe asked what, exactly, Tristan was talking about, he sheepishly said, "Listen, I’m just saying, True does need a sibling."
"I might get some embryos and get a sibling," said Khloe, who has been vocal about freezing her eggs in previous episodes. "I might need to borrow some sperm or get some from you…we’ll figure that out later. That’s a whole other episode."
Keeping Up With the Kardashians airs Thursdays at 8 p.m. ET/PT on E!.