Sia Visits Howard Stern

Sia, the secretive songwriter behind some of the biggest hits on the radio stopped by the Howard Stern Show Wednesday.

The singer/songwriter, who has crippling stage fright, has written for Rihanna, including the hit "Diamonds," which Stern -- who normally likes hard rock -- has always talked about enjoying. She also penned hits for Britney Spears and Beyonce.

Sia does not allow herself to be photographed -- which Stern complied with -- posting only pictures of her from the back on HowardStern.com.

Though in most cases that would seem like a calculated affectation Sia seems to actually be scared of the spotlight which is why she has given away some of the biggest hits of the past two years letting other artists become famous (or more famous) off of her work.

Stern went through a list of the hit songs Sia has written> These were the highlights.

Diamonds - Probably Sia's most famous song, wasn't written with Rihanna in mind.

Pretty Hurt - Katy Perry loved the song so much that she texted Sia saying she was 'pretty hurt' that Sia didn't offer the song to her.

Sia told her to check her inbox, because she had sent the song to Katy months before.

Titanium -This one was intended for Alicia Keys, but DJ and producer David Guetta liked Sia's demo vocals so much that he used them.

Wild Ones - A huge hit, that Sia sang although she didn't want to because of the lyrics (which she wrote).

Sia has a new album coming out July, 8.