Myleene gave birth to a baby girl weighing 6lbs 2oz on 25 March.
Klass and her husband Graham Quinn decided to call her Hero.
The couple already have a child together, three-year-old Ava.
Simon Jones, Klass' spokesman said: "Mother and baby are both very well. Myleene, Graham and Ava are all very proud and excited about the arrival of baby Hero."