There is a new movement capture system available for actors, that involves covering them in phosphorescent green goo, but allows them to be morphed into other people much more realistically. (See link for more details.)
So this service will provide prepped actors for your wedding, baptism, bar mitzvah,
funeral, whatever, and then superimpose the celebrity/ies of your choice in the event video (subject to licensing, of course).
Also available for corporate endorsements (for a much higher fee, naturally).
And for the vain, we can make the bride and/or groom and/or various relatives look younger, thinner, blonder, whatever. Provided they're prepared to swear their undying bliss covered in that green goo.