The movie was the ninth and final on-screen pairing of Tracy and Hepburn, who had a long and semi-public romance in real life. Everyone involved knew Tracy was sick during the filming, and the legendary actor died exactly 17 days after this last scene was shot. (My wife is convinced that the moment when Tracy gazes at Hepburn at about 4:30 in the above clip was genuine, maybe even unscripted.)
If you haven't seen it, you really should.
P. S. The role of Joanna, Tracy and Hepburn's daughter in the movie, was played by Katharine Houghton, Hepburn's niece.