Donna Summer told Fresh Air about how she came up with the song and imagining herself as Marilyn Monroe to sing it [lightly edited]:

I ran into the studio, and I said, Giorgio, I have this idea. Do you think you could write something to it? And I sort of sang it to him, and he kept saying it over. He says, love to love you. I love to love you. He kept rubbing his chin and thinking like a little mad scientist. And then he went into the studio, and Giorgio had written this track. And he asked me to go in and start singing something, and I didn’t have any words other than love to love you, baby. So I was improvising on the track live. And that really became “Love To Love You Baby,” the original track.

The vocal was breathy and airy. And basically, I was a theatre singer, so I had been much more of a belter. And it was really different and difficult for me to tap into who this person was. And so I imagined Marilyn Monroe and just began to think, well, how would Marilyn sing this song? And she would be very soft. … Through her, I began to understand who the song was for and who the song was about and the girl singing it. And I tapped into it and recorded it.

I laid on the floor. And it was very difficult to do this because I was a comedian, and Giorgio and I were always goofing around. So Pete and Giorgio had to turn the lights down. And I think they might have brought some candles in the room or something. And I literally laid on the floor. They lowered the microphone to me, and I just, you know, kind of sang it like I was, you know, having a romantic encounter (laughter). It’s embarrassing to me to say this now, but it’s true. And we nailed the song, finally. And like I said, I came up with some vocal approaches that basically no one had ever done before. So it kind of started the whole thing of this new type of music.

— Donna Summer, Fresh Air, 2003