Generally you need a connection to the person and they need to be aware you exist. You may also need something personal belonging to them, more than a downloaded image, but a personal item or connection.
If love spells worked on celebrities, you would see a lot more celebrities falling in love with random people, but they don't.
I highly agree with Hearthwitch. But many people have opinions on love spells, and that is one of the most common subjects on here and why most people seek magick. In my opinion, love spells will not manipulate someone to love you. Magick does not work against free will. As Hearthwitch said it's very unlikely, I have had a few people ask me this before, if you had a special bond with a certain celebrity there is a chance one would work, but if it's someone that doesn't even know you exist I can guarantee it will not work.
People saying that "magic doesn't manipulate free will" are objectively wrong. There are paths where people view it as wrong to manipulate free will, but magic is more than capable of doing so.
Celebrities are no different to other people, the only difference is that there is likely more people casting spells on them. If there are a number of different love spells on the same person, then you may find your results lessen sightly.( I'm not saying this is definitely the case, just that the contesting spells could cancel to an extent)
The biggest obstacle would be meeting the celebrity in a social context. If you're able to achieve this, then I'd imagine your spell would work well.
Actually knowing someone isn't really necessary, just makes it easier. So long as you can get a feel for their aura, you'll be able to cast on them.
Re: Love Spells on Famous By: Weatherwax / Knowledgeable
Post # 7 Aug 08, 2017
In short, a love spell can work on anyone, however on someone who does not know who you are, has never even heard of you, and you don't have access to certain ingredients - let's not forget a lot of them are happily partnered already.