Well when i was there in 2000 & 2004, I never got to meet any stars. Wished I had though. The closest to a famous person that we met was a Lookthung Singer when we went in 2004, her name is Angkana Khunchai. She knows my aunt who was also visiting Thailand from France. She took us shopping in Mukdahan, where she did a lot of bargaining for us.
We also went to Khao San Road in Bangkok, we didn't run into any stars, but there's a lot foreigners who go there to eat and shop. We went at night, and it was booming with a lot of people and it was fun.
There's this one mall that we went to but i can't remember the name, but it was like 4 levels to the mall.
the 1st level was the food section, like a grocery store, and other food that they sold, more thai food, and they had a cd section on this floor too, 2nd and 3rd floor were clothes and what not, and the 4th floor had entertainment stuff, like games and arcades, restuarants (mainly the types of restuarants that we have here in America (such as pizza hut, we ate there, and their sizes compared to ours is not the same), they also have a swimming pool area on the 4th floor.
Just thought you might want to go to these places even though you might not run into any stars.