To promote its batteries for National Hearing Month in May, Duracell has enlisted Mad Men's John Slattery for a voiceover in a touching video to support its giveaway of 50,000 free hearing tests.

The "Stay Connected" film from Anomaly, directed by Park Pictures' Vincent Haycock, tells the story of a grandpa who's losing out on some key things in life -- like hearing the grandchild he's babysitting crying in the distance -- because of hearing loss.

The condition affects 48 million Americans, but 80% of those over 65 who are affected don't seek treatment, according to Duracell, recently sold to Berkshire Hathaway from Procter & Gamble Co. The free tests can be done via touch-tone phone, administered by the non-profit group National Hearing Test.

This story also appears in Ad Age's the Lowdown.