The rapper and business mogul - who already has an eight-year-old son, Christian, with long-time girlfriend Kim Porter - officially announced the pregnancy yesterday.
A spokesperson for the couple said: "They are thrilled about the news."
Friends began to suspect that Porter might be pregnant when she didn't drink any alcohol during the couple's visit to St Tropez this summer.
Then, at the photo shoot for the Unforgiveable advert in Monte Carlo, Porter aroused further suspicion she might be pregnant when she wore loose shirts.
Source: Stuff