The 'Cosmopolis' star started to chew on the small wooden sticks to keep him busy while he withdraws from nicotine, and now fans keep giving him boxes of them wherever he goes.
He told GQ magazine: "I quit smoking the other day and didn't even really realize I'd said anything about it.
"I've been chewing these f***ing toothpicks all the time. Someone noticed in Cannes and literally the next day in Lisbon, then in Paris and in Berlin there were about 20 people on the red carpet giving me huge amounts of toothpicks. Thousands of them."
Robert - who is dating his 'Twilight' co-star Kristen Stewart - enjoys like the attention his fans give him, and even once took one devoted admirer to dinner when he was shooting in Spain.
He explained: "I was playing Salvador Dali and there was this one girl waiting outside my apartment every day for about three weeks. There was one day when I was just so chronically bored I said to her, 'Do you want to just go to dinner or something? No one else wants to hang out with me.'
"Her parents had a restaurant, she took me there and I complained about everything in my life for about two hours, then she gave me the bill to pay and was never back outside my apartment ever again."