U.S. model Amber Rose announced Thursday she is pregnant with her first child. Rose, 28, is engaged to rapper Wiz Khalifa, 24. "We do know the sex, but we're [keeping it private] for now," Rose told People.com at the MTV Video Music Awards show in Los Angeles. "We just found out two days ago, so we're super excited." "I'm superman!" Khalifa told the celebrity news Web site. "I'm going to the best dad and the best performer and the best husband that I can be." The couple did not reveal the baby's anticipated due date.