Who Is Lindsay Lohan's Valentine?

Looks like Lindsay Lohan is preparing for a V-Day lovefest ... but who is the lucky girl/guy?

Late last night Lilo tweeted, "Yay!!! I have a Valentine!!!!!" but didn't give any other details about her sweetheart or her plans for the evening.

She was recently snapped stepping out with Dennis Hopper's son Henry in Venice, but we're still not sure of they're just friends or fooling around.

Any chance she's rekindled something with former flame Samantha Ronson? Or is there someone else in the picture?

Your guess is as good as ours!