Bond is "treated" to a Black Velvet as part of a seafood dinner in Diamonds are Forever.
The Black Velvet is within the rare cocktail family known as "funereal." It originates as the funeral cocktail for Prince Albert, a mix of champagne and Guinness, that was originally served in tankards. If this sounds suspect, dubious, bitter, uncomfortable or unpleasant, it is because you keen deduction skills are advising you of the truth.
This is a bad cocktail.
But many things are bad and your job is to cope, mend and manage these things. The Black Velvet can first be helped in mitigating its size: a tankard, that is to say a British imperial pint of 22 ounces, 11 if which being Guinness ande r the remainder being champagne is a bit much to tuck into. A Black Velvet, served in a flute, a 3 ounce pour of each component, is enough of a serving for most.
Secondly, a toasty bitter Guinness cut with an austere, hollow prosecco is like having fillet of sole with claret- that's not cricket. It is rare to find a time, occasion or purpose to release demi-sec or even doux, the sweetest champagnes, but if ever the time is right, it is to battle the stout monster that is a Guinness stout. In cocktails, chocolate or conversation, balance bitter with sweet.
1 part Champagne- Doux or Demi Sec
then gently layer
1 part Guinness