Yes, I have, and it is so cool. Sometimes they might have their handler with them, and the handlers make it somewhat difficult to actually talk to the celebrity, but as long as you don't act crazy, they are pretty regular and will chat with you. I've taken pictures with many of them at these parties, movie premiers, movie screenings, etc.. They are usually there to be seen and photographed... it's like a gig for them, and I don't mind walking up to them and chatting and asking to take a picture with them. Heck, if I am invited... I consider myself a celebrity as well. lol. You'll know the ones that really don't want to be bothered. lol. Now when they are out having dinner, or with their family, I take it as that they are off the clock, and it's their personal time... only if they make eye contact with me, smile, give me a compliment, and/or start up a conversation with me, then it's fair game. The trick is to get invited to these events. Also, now one has to consider what happens now after Social Distancing measures are now in place... I can only speak about my experience(s) in the Pre-Social Distancing Era.
"J!m"