She was born with the name Amanda Lee Rogers. She changed her name to Portia de Rossi when she began modeling and acting (she apparently just liked the sound of it). She married Ellen DeGeneres in 2008. And then in 2010, she had her name legally changed to Portia Lee James DeGeneres (although she still uses Portia de Rossi professionally).
Okay, she’s been calling herself Portia for years and she’s probably used to that. Lee is part of her original name and DeGeneres is her wife’s name. But does anyone know where the James comes from?