The boyband's former manager Daniel Glatman has claimed that it is "reckless insanity" for the group to put themselves up for the annual competition.
However, singer Duncan James told BBC Newsbeat: "There's been a lot of negativity but all we ask is, please hold off until you hear the song. We believe it's one of the best songs to enter Eurovision in a long time."
Bandmate Simon Webbe added: "Everyone is entitled to their own opinion. Obviously we don't agree with [Glatman]. We believe this is going to be the best springboard for us to come back on.
"Who are we to actually think we can just waltz back in with a song and expect everyone to like it? At least this way we can reach 125 million people across Europe and represent our country whilst doing so. There is no other platform like it."
He added of the James and Lee Ryan-penned 'I Can': "It's very anthemic. It's very positive. It was a no-brainer for us. This song for us we feel is Blue; this would have been our first single whether it was for Eurovision or not."