If you have not read the book on Badfinger you should.  It's written by Dan Matovina & covers many details. Harry Nilsson was at a party when he had heard Without You on No Dice.  He loved the song so much he opted to record it.  While in the studio, Badfinger was apparently down the hall and dropped in too surprisingly find Harry recording one of their songs.  In the first one thousand pressings of the book a CD was included.  You can hear Pete's (verse) version and Tom's (chorus) version