Besides being two of my favorite J-pop bands,Princess Princess and Chisato Moritaka had a pretty close relationship going on at the time.I would frequently see pictures of Princess Princess concerts where Chisato came onstage to perform a song or just to say hello the audience, and Chisato was one of the guests (along with Arisa Mizuki and Hiroko Moriguchi) who helped send off Princess Princess on their final Music Fair appearance.
Recently browsing through the various Princess Princess clips uploaded on Youtube, I came across two performances featuring Chisato Moritaka and Princess Princess signing together onstage, one featuring Chisato singing "Diamonds" with the girls, and this incredible performance of the group backing up Chisato on her KOKON TOZAI song "Teriyaki Burger"... I just love this clip, because besides the fact that Puri Puri's skills and singing really beef up the song,I love watching the SHEER JOY they're all having performing, especially Kaori!
This terrific performance is from the 1991 NHK Xmas Pop & Rock Special. Sugoi!