Kardashian sisters react to Rob's engagement on 'Keeping Up'

LOS ANGELES, June 20 (UPI) -- The Kardashian sisters were initially less than pleased when they learned of Rob's engagement.

Kourtney, Kim and Khloe Kardashian reacted with shock and anger to the news on Sunday's episode of Keeping Up with the Kardashians. Rob proposed to Blac Chyna in April without telling any of his family members.

"Rob is such a [expletive]," Khloe told Kourtney and Kim. "She said he proposed in front of her whole family at her house last night. So he's engaged to Blac Chyna and you don't even tell your sisters?"

"We are all reacting differently to this news," she added in a confessional. "And as we should. He never mentioned anything, not even an inkling that this was about to happen. Finding out on social media leaves a really bad taste in my mouth."

Kourtney was the only one to defend their brother, calling Kim "a [expletive]" for saying Rob is "a lunatic." She suggested he kept the engagement secret because his sisters are "clearly" judgmental.

The Kardashians have come around to support Rob's engagement. There were prior concerns about Kylie Jenner dating Blac Chyna's ex-fiancé, Tyga, but Kim said she and her family are "all on board" in the July issue of GQ.

"We definitely see that my brother is happy and getting healthy, and whatever gets him to that place, you know, we're happy for him," she said. "Chyna's a sweet girl, and I think we all have so many things going on in our lives that we just want my brother to be happy."

Rob and Blac Chyna announced in May they are expecting their first child and will document their relationship in the new E! series Rob & Chyna. Kylie and Tyga had split earlier in the month.