The Kardashians are in for the surprise of a lifetime on this Sunday's episode!
On the next Keeping Up With the Kardashians, Rob Kardashian meets with Kim Kardashian, Khloe Kardashian and Kourtney Kardashian to talk about his engagement to Blac Chyna, but there's "one more thing" he has to tell them about.
In this clip from the episode, Rob tells his sisters he's "very happy" about his engagement and explains that it happened "spontaneously" so that's why the Kardashians "weren't in the loop."
The girls then tell Rob that he should've said something to them before it happened.
"Do you understand that that was hurtful to us that we found out about your engagement on social media? I think we just want that acknowledgement," Kim tells Rob.
"Yes I understand but I wasn't even thinking that at the time it happened so fast," he explains. "I get I upset you guys, I get I'm your brother, only brother, you would like to know when something important like this happens. I apologize because I wasn't trying to be rude."
After talking to the trio about his engagement he tells his sisters, "And then there's one more thing I have to talk to you guys about, but I don't want you guys to get mad."
Take a look at the clip above to see the family talk about Rob's engagement and see Kim, Khloe and Kourtney's reaction when Rob says he has "one more thing" to tell them!
Watch brand new episodes of Keeping Up With The Kardashians Sunday at 9e|6p, only on E!