The 40-year-old star, who played the role of Barney Stinson in the hit TV series, said that his co-star, actress Cristin Milioti made him cry with her performance in the finale, reported Contactmusic.
"We never talked about the end. Josh Radnor has never been funnier and Cristin Milioti made me cry," he said.
Neil said that the final scenes stirred strong emotions within him.
The actor said he had even persuaded the show's producers to tell him how the show concludes when he was drunk.
"After, like, five drinks, I cornered our producers at our Christmas party and said, 'Spill the beans. Tell me how it all ends.' And they did. It's more complicated than you'd assume. Fans won't be disappointed," he added.
The hit sitcom comes to an end after running for nine successful seasons.