Patti Labelle joined Marsha Ambrosius on stage during the Philadelphia stop of her BET Music Matters Tour with Melanie Fiona. The singers spoke to the crowd about their love for each other and working together before joining forces on a live rendition of Labelle’s hit “If Only You Knew”. And what a live rendition it was! They damn near tore the roof off that venue. What a lucky a** audience!