It is currently unknown if this card will be available to the general public. However, the card does have a special set symbol. It also seems to be illustrated by nagimiso.
Stay tuned for more on these special P25 Music cards!
Major update: Katy Perry V and Post Malone V have been revealed on the official Pokemon 25 music site. Also high resolution images of these cards have been revealed alongside them. The card numbers are not numbered as a set but appear most likely to be numbered after their birthdays.
''This special Pokémon TCG card is for promotional use only. Katy Perry was gifted with a printed version of this card as a special thank-you for her collaboration and contribution to the program. Currently, there are no plans to print this card for consumer use or purchase.''
Thank you Super_Franky for informing us.