The openly gay star made a public statement in front of a global audience of millions on Wednesday night by planting a smooch on the lips of a male dancer during the show's opening number.
The kiss, which hit headlines around the world, took place during a segment dedicated to Gretna Green, a village in Scotland famous for hosting runaway weddings, and the two men were surrounded by pairs of male and female dancers with the women wearing bridal veils.
Barrowman has now revealed his stunt led to a volley of criticism on Twitter, and he has retweeted a number of the nasty comments on his own page.
In a series of posts on the social networking website, Barrowman hit back at his critics, writing: "I am retwtin (retweeting) the neg (negative) because I want u (sic) all to see how bitter and nasty and neg (sic) some people r (are).
"I am so happy right now... I'm Scottish and u (sic) can never take that away no matter what your politics are. Bitterness makes u ugly and old very fast (sic)... happy... I don't care (what they are saying)."