Amber Rose and Wiz Khalifa are having a baby boy.The model - who is expecting her first child with her fiance - accidentally revealed the sex of their forthcoming child on social networking site twitter in a tweet thanking one of her friends for purchasing an all in one sleepsuit decorated with a picture of Guns N' Roses guitarist Slash for their baby. She wrote: ''My friend Maria bought our Lil Boy this Slash onesie..... Oops did I say Lil Boy??? ;-) (sic)'' It is not known whether the 29-year-old beauty - who is in her second trimester - genuinely meant to reveal whether she is having a boy or a girl, but earlier this month the 'Black and Yellow' hitmaker refused to say whether the couple are having a son or a daughter. He said: ''I do know, but then [Amber] told us not to say yet. We'll wait until she's ready.'' Amber recently admitted she is planning to have an all-natural water birth without the help of medical aid, and the couple confirmed they are keen to resume planning their wedding after their son is born. She said: ''I'm so ready. I've decided that I'm going to have an all-natural water birth. No medicine. I want those bragging rights! The next time Wiz has a stomach ache or anything, I'll say, 'I popped out a baby all-natural.' '' Wiz added: ''It makes more sense for the baby to be in the wedding than for her to be pregnant. Some people, they rush and do it, but it works both ways.''