Now everybody has a smartphone in their pocket, there's an easy way to document that chance meeting with your favourite actor or singer.
We asked readers on our Facebook page for their starriest shots and were inundated with famous faces.
Here are another 18 of the very best, in the third of our picture galleries.
See the second part here.
1. Sir Rod Stewart
Karen Brocklehurst was delighted to get her picture taken with the rocker.
2. Richard Jobson
Grant Mcnaughton posed with the Skids lead singer.
3. Jamie Dornan
Lynda Cairns was lucky enough to bump into the Fifty Shades star at a party in Edinburgh.
4. Steve 0
Murray Neil Johnstone posed with the Jackass star at Edinburgh's Liquid Rooms during the Edinburgh Fringe.