There may be something in the water because it look like there's a baby boom going on with the Kardashian clan.
The TV star, 33, is believed to be three months along. It will be her first child.
According to TMZ, Khloe "conceived naturally" and doesn't know the sex of the baby yet.
The report comes just a few days after multiple outlets reported that Kylie Jenner, Khloe's half sister, is pregnant and due in February. Meanwhile, Kim Kardashian and Kanye West are expecting a baby in January via a surrogate.
Khloe, who's been dating Tristan for about a year, has made no secret of her desire to be a mother. Her beau is apparently ready for a big family, too.
On the Season 13 finale of "Keeping Up with the Kardashians," Khloe joked that Tristan wants "five or six kids with me."
"We could start at one and then grow from there. But now, knowing I'm not on birth control, it's really scary. It's like a really big step," she said.
In April, a source told Us of Khloe, "She definitely wants a big family. She wants multiple kids."
The reality TV star is incredibly confident that the NBA star is the one for her.
"I'm in the best relationship I've ever been in and it doesn't take a ring for me to feel that way," she told You magazine after being asked about engagement rumors. "My boyfriend is very protective of me. Feeling loved and validated and secure is a huge thing. Tristan is protective of my entire family, which is beautiful. And I love that everything we do is as a union. When he speaks, it's 'us' and 'we,' and that's important because it shows that you're sharing life."
Tristan is already a father, as he shares a 9-month-old son, Prince, with his ex-girlfriend Jordan Craig.