Pop princess Britney Spears has confirmed rumours she is pregnant with her second child by making a surprise appearance on US TV programme The Late Show With David Letterman. The TOXIC hitmaker appeared on the show with eight-month-old son Sean Preston to make the happy announcement, according to TMZ.com. Spears, who married rap wannabe Kevin Federline in September 2004, has been dogged by rumours of a second pregnancy since pictures emerged of her rounded midriff. Last week (04MAY06) Spears called a press conference where it was widely assumed she would reveal the secret, but mysteriously failed to show. Prior to the US programme's taping, Spears was spotted shopping in exclusive French baby boutique, Jacadi. Talking to Letterman the pop beauty quipped, "Don't worry Dave, it's not yours." While the new arrival will be Spears' second child, it is the fourth for Federline - he has two children from a relationship with former love Shar Jackson.