Hilarious behind-the-scenes stories show what it's really like to be a photographer on set with celebrities

Portrait photographer Chris Buck has interacted with some pretty big personalities while on set. From Barack Obama to Willie Nelson, Buck has been photographing actors, musicians, and politicians since the mid-1980s.

His images have a sense of humor that he describes as "uneasy," which, as it happens, is also the title of his new book of more than 300 portraits. Placing his subjects in what some might consider "uncomfortable" positions, Buck has collected a mass of interesting photographs, as well as some fantastic stories from being on set.

Here are our favorite behind-the-scenes stories from his latest book. All captions were provided by Buck.