If you search for an actor/actress in Google and then click on the “People also search for” section in the knowledge graph, Google will show you the bacon number or the connection/relationship between the first person you searched for and the second person you clicked on. Again, this is clearly a Hummingbird advancement.

This works both on mobile and desktop:

This, I believe, was first spotted by John Doherty on Google+.

Forum discussion at Google+.