This is the problem with all these 'heavyweight' American stars coming over to the West End to earn their theatre browny points: the Infamous British Tabloid Press ©.
What did David Schwimmer expect? He's an ex-Friend, making his UK stage debut, during which he has to strip down to his undies. Did he really think that some enterprising papparazzi wouldn't get himself a ticket and just happen to bring his telephoto lense along?
If it's good enough for Kathleen Turner and Nicole Kidman, then it's good enough for 'Ross'.
According to this report Schwimmer was upset by "the snapper [who] ruined his West End debut...by taking non-stop pictures from in the stalls of the Gielgud Theatre in a sequence which involved the 38-year-old stripping down to his underwear.
Schwimmer himself is quoted as saying "I was the only person who saw him and because I am on stage all the time I couldn't tell anyone, but I was willing to walk off."
But he didn't of course. He soldiered bravely on (in his keks) to predictably mixed reviews.
P.S. Do you like the picture we found? Isn't it great! "Bang...I'm so dangerous...just look at my dangerously well-defined parting".