I never heard of this: Shaun Cassidy sings Illia's theme:

[Maurice]

Wow! Ilia's Theme really is obscure! Who knew this existed?

Lots of us!

To say nothing of Shaun Cassidy, but that's to be expected. He wasn't very talented, now, was he? Maybe he was an actor-turned-singer, or something like that?

You're showing your (young) age. Shaun was TV royalty!
http://www.imdb.com/name/nm0001027/

He was in "The Partridge Family"! I know about that! 2takesfrakes, how old are you?

David Cassidy was in The Partridge Family, not Shaun.

 

[Peach Wookiee]

Lots of us!

You're showing your (young) age. Shaun was TV royalty!
http://www.imdb.com/name/nm0001027/

He was in "The Partridge Family"! I know about that! 2takesfrakes, how old are you?

David Cassidy was in The Partridge Family, not Shaun.

Oops!

 

[Therin of Andor]

He was in "The Partridge Family"! I know about that!

No, that was David Cassidy.

According to IMDb, when Shaun's mother, Shirley Jones, and half-brother, David, were both starring in The Partridge Family (1970), he asked his mom to put him in some episodes. However, she refused as she wanted to encourage him to concentrate on his schooling.