It's mentioned throughout the movie, they are watching it on Conan as Cruise and Cruse fall in love that first night, some others too.
The ending is whatever, it probably would have been a stronger movie overall, to not use that ending, and write the script a bit differently, but the parts are so good, it outweighs a possibly questionable/bullshyt ending. I didn't get it 100% when I saw it, and probably still now but you don't need to, to appreciate the movie as a whole.