Kimora Lee Simmons is pregnant with her fourth child and expecting her first with husband Tim Leissner. Credit: Araya Diaz/Getty Images

Fourth down! Kimora Lee Simmons is expecting baby number four, a source confirms to Us Weekly.

This will be the designer's first child with her second husband, investment banker Tim Leissner, whom she married this past February.

Us confirmed that Simmons, 39, and Leissner had secretly wed, after her ex-husband, Russell Simmons, revealed the news via Twitter. "All of us love @OfficialKimora but the fact is she is happily married," the business mogul wrote. "Tim has been family for a while now." (Simmons was married to the Def Jam co-founder from 1998 to 2006. Their divorce was finalized in 2009.) See pics of Kimora's wedding ring.

Simmons has two teen daughters with her ex: Ming, 14, and Aoki, 12. She also shares a son, Kenzo, 5, with Blood Diamond actor Djimon Hounsou. The former model and Hounsou were together for five and a half years, before his rep confirmed to Us in November 2012 that they had split.