But thousands of miles away in Italy her famous mother, Kris Jenner, 61, claimed that she was just as surprised about the news as the rest of the world.
Waking up in Milan on Saturday – where she was attending the Bottega Veneta MFW show – she said: "It wouldn't be the family if something didn't happen every single day."
When asked if she knew the news was going to break about Kylie she replied: "I just woke up this morning, She's not confirmed anything. I think it's kind of wild that everyone is just assuming that that's just happening."
While she refused to confirm or deny the pregnancy news she did relate the story to her own first pregnancy, when she was expecting daughter, Kourtney Kardashian, back in the late 1970s.
She recalled: "I got so big, all I could do was go to Bottega Veneta and buy the most amazing handbag I could find… and carry it around in front of me."
Kylie, 20, and her 25-year-old rapper boyfriend had broken the happy news to friends earlier this month at the Day N Night Fest in Anaheim, California.
It is even claimed that the couple know the sex of the child - and are having a girl. She is believed to be at least three months pregnant, the couple started dating in April.