Simplify the following text for a Grade 12 native English-speaking person.
Original: In addition to singing , Duff has also wrote and co-wrote several songs for her sister Hilary 's studio albums , Metamorphosis and Hilary Duff , as well as the song `` Gypsy Woman '' , on Hilary 's third studio album , Dignity .
Simplified: Duff wrote or co-wrote several songs on two of her sister Hilary 's albums , Metamorphosis ( 2003 ) , Hilary Duff ( 2004 ) and the song , `` Gypsy Woman '' , on Hilary 's 4th album , Dignity .