The Welsh fullback posted a short video of himself sitting at home with his family while the announcement of the squad was being read out live on television.
The list was read out in alphabetical order, and when Halfpenny's name was read out the elation was unmissable.
The 28-year-old played in all three Lions Tests against Australia in 2013, winning man-of-the-series award as his side won the series 3-0.
In 2009, Halfpenny was due to feature in the Lions series against South Africa, but missed out through injury, playing just one tour match against the Free State Cheetahs.
With 74 Test matches to his name, a Lions call-up still means the world to Halfpenny.
The Lions play seven tour matches and three Tests against the All Blacks on their tour.
What a feeling AllForOne pic.twitter.com/R6xjbtIeHl
- Leigh Halfpenny (@LeighHalfpenny1) April 19, 2017