"Magnum P.I." actors Tom Selleck and Larry Manetti are leaving fans nostalgic. The dynamic duo was seen together for a mini-reunion as Manetti prepared for his feature on Selleck’s drama series "Blue Bloods." Selleck’s "Blue Bloods" co-star Donnie Wahlberg took to Instagram Monday to share a picture of his cast members. "#MagnumMonday! It’s a mini Magnum PI reunion, on the set of #BlueBloods this week, with guest star Larry Manetti & Tom Selleck — together again.