What's The Sex Of Wiz Khalifa And Amber Rose's Baby?

Wiz Khalifa and Amber Rose tried to keep their lips sealed on this one, but someone was bound to slip up sooner or later.

The expecting mother was celebrating her birthday on Sunday when she coyly dropped the news. "My friend Maria bought our Lil Boy this Slash onesie..... Oops did I say Lil Boy???  ," Amber tweeted while sending an Instagram with the white onesie that featured an image of the iconic Guns & Roses guitarist.

MTV News caught up with the Pittsburgh rap star on the red carpet for the 2012 BET Hip-Hop Awards and asked about the sex of the couple's upcoming bundle of joy, but Wiz wouldn't spill the beans. "I do know, but then [Amber] told us not to say yet. We'll wait until she's ready," he told us.

No telling if the Twitter reveal was part of Amber's plan, but what's done is done.

Neither Khalifa nor Rose have revealed when the baby is due however, but they are fast preparing for the blessed event. One of the tasks at hand is choosing a name. "We're working on it. You know how difficult that is," he said with his patented Khalifa laugh. "But it's all good, though. I let her have her way all the time; that's my baby."

The couple, who are engaged to be married, also appear on the October/November issue of XXL magazine. In the issue, Amber talks about her plans for a natural birth. "I'm so ready. I'm going all-natural. I've decided that I'm going to have an all-natural water birth. No medicine. I want those bragging rights," Amber told the mag. "The next time Wiz has a stomachache or anything, I'll say, 'I popped out a baby all-natural.' "