You are using an older browser version. Please use a supported version for the best MSN experience.

‘NCIS’ Star Mark Harmon on His Son’s Appearance in the 400th Episode (Exclusive)

ET spoke with 'NCIS' star Mark Harmon about his son returning again to play young Gibbs for the 400th episode, airing tonight on CBS.

UP NEXT

UP NEXT

More From ETonline

More From ETonline

image beaconimage beaconimage beacon