Troy Verges and Hillary Lindsey discussed the writing of the song in an interview with The Boot
Troy Verges: It was written for the film; we read the script and wrote it for the story.
Hillary Lindsey: In the script, it says, "Kelly (who is played by Gwyneth) enters the stage to sing her grand finale performance of 'Coming Home.''' So the title was already give to us. Tom, Troy and I read the script, and we had to incorporate what 'coming home' meant to her character in lots of different ways. It's metaphorical for a lot of other things that were going on in her life.
Troy: Tom actually walked in with the first few lines of the verse, because he's just a great lyricist. We took that seed and grew it from there. Her character has the prodigal son thing going on in a way. She's a really diverse character. There's lots of coming home angles for her, and we tried to hit all of them.
Hillary: She's very strong and she's very put together, but in the same breath she's very tormented and very fragile and falling apart.
Troy: We didn't want to make it so tied up to her character that it felt like it was manufactured.Hillary: She's supposed to be an artist, so it would be something personal to her that she would sing but it wouldn't be so specific.Troy: It only took a few hours of just starting it and having the first draft of it done, and we were pretty excited about it. We did tons of rewrites on it after that. We tried putting a bridge in, then took it out, to get it just right for the filmmakers.
Hillary: We were rewriting because we'd submit it to Randall Poster, who was the music supervisor for the film, and he would come back with feedback. It was really great. We weren't rewriting just shooting in the dark. We were rewriting with direction.
Troy: We started it before Christmas and then we came back, so it was about a month of five meet ups to write it.
Hillary: It was funny when we saw it, but I remember being surprised that this was the
song Gwyneth and Leighton Meester were fighting over. It was a little weird. It made me feel good. But it was like, "When everybody leaves the theater, they better really like that song!" It was a little bit of pressure.
Troy: I thought that was cool, because that happens. People fight over songs all the time, and I've never seen it in a movie like that. And then being nominated for an Oscar wasn't even in the realm of possibility. I watched the Oscars growing up, but I never thought I'd be nominated for one.