Many thanks to mammahverdagen for sharing a photo on webstagram that she and a friend took with Keanu Reeves in Central Park about 10 years ago.
Update: Many thanks to @xRubyBijoux who has tweeted a second photo from this run in on twitter. She also posted it on webstagram.
Update X2: @xRubyBijoux has confirmed on twitter that the photo was taken in June 2005 in Central Park.