What is the commercial song Princess Diana sang right before her wedding?

Question

There was a documentary about Diana where it was mentioned that she and her wedding people were watching TV coverage of her wedding, right before it happened. Then came on a popular commercial. She and her hairdressers sang along.. What is it?

Answer 1

Some kind of cookie jingle - can't remember.

Just one cornetta or something like that

Answer 2

Ah, yes... the other poster is quite right.  "Just one Cornetta..." was a massively popular tv jingle for Cornetta Ice Cream treats, the summer of the Royal Wedding of Prince Charles and Lady Diana Spencer.

The advert came on the telly whilst those assisting Diana were watching the pre-wedding coverage, and they apparently latched on to the silly, opera-style tune as the perfect roundelay for the moment.  It became something of a running joke that afternoon.

Most memorable of all, according to the designer's of Diana's wedding dress, David and Elizabeth Emmanuel--  as they stood by waiting for the magnificent royal glass coach to leave Clarence House, Diana leaned over and burst into one more operatic "Just one Cornetta..." leaving everyone in "stitches" as the coach pulled away.