Khloe Kardashian felt "internally sad" when Rob Kardashian announced he was expecting a baby with Blac Chyna.

Rob started dating Blac in January (16) and they got engaged in April (16) without telling his family, who all found out about the proposal on social media while on holiday.

On Sunday night's (03Jul16) episode of the family's reality show Keeping Up with the Kardashians (KUWTK), Rob explained to his sisters, Kim, Khloe and Kourtney why he didn't warn them about the engagement. He also revealed that he and Blac were expecting.

Khloe buried her head in her heads and could barely look at Rob as she grumbled "Congratulations" after her sisters. However, she revealed how she truly felt to the camera.

"I don't know my emotions right now," Khloe said. "I feel more empty and unresolved than anything else and I'm internally sad."

In the footage, Rob told them, "She didn't want me to say anything to mom and you guys until she was three months, but I want mom and you guys involved... I'm excited. I know you guys probably feel weird. I don't expect you to be all happy but I'm sure you will eventually.

"There needs to be a talk between all of you guys because she's not going anywhere. She knows I'm going to be in her life, she knows you guys aren't going anywhere. I don't want it to be where y'all don't have a relationship. That's just weird."

Since the episode was taped, the sisters, plus half sisters Kylie and Kendall Jenner and mum Kris Jenner have been spotted bonding with Blac, who had a fraught relationship with the family because of her former relationship with Kylie's on-off boyfriend Tyga. Blac and Tyga have a three-year-old son together.

Kylie posted a selfie with Blac in April (16) and wrote on Snapchat, "When we've been best friends the whole time." But the latest episode of KUWTK revealed that Khloe was blindsided by their new friendship.

"I'm just so confused," she said. "Seeing this picture of Kylie and Chyna together I legit thought it was photoshopped at first," while Kylie explained she wanted to have a happy family so "people need to make up and get over things."

Blac is reportedly set to make her debut on the series as she attended Khloe's 32nd birthday party, which was filmed for the show, in June (16).