On Sunday, she will take to the stage alongside the other five remaining acts in her bid to make it to this year's final. Happily married Kelly, who is a member of the Travelling community, will perform the Sarah McLachlan hit In the Arms Of An Angel.
But former Westlife star Kian reminded the Cork native it is all about the performance and publicity doesn't always turn into votes.
Cian (33) told the Herald: "I did sit her down at one stage and say 'listen love, it's about your singing, come on, let's refocus now'.
"She might be the most famous act on the show, but that doesn't mean she will win it. I think she did get a little carried away with all the press attention, but it's the votes that count," he added. The pair have become close throughout the show and Kian says that he is a big fan of the singer and that she did listen to his advice. "There was a big difference between her first live show and her second live show, where she had an amazing performance.
"She's a great girl and, with her husband (Bernie), they make a lovely couple – at the end of the day the baby is the most important thing."
Babies is a subject that the blonde crooner knows a thing or two about – he has a son Koa, 18 months, with wife Jodi Albert. But, Kian says there is no strategy when it comes to Kelly's impending due date.
"Ideally it would be better for me if the baby didn't come and if she doesn't give birth before the final. She will be five days overdue if she doesn't, which isn't that unusual.
"She keeps saying that she will be able to sing after giving birth, but I just laugh," said Kian. "I know from my own wife that if she gives birth on the Saturday, there is no way in the world that she will be on that stage on the Sunday."
Despite being a firm show favourite, Kian says that he will stick to the rules and if Kelly can't perform, then she will be out of the show.
"If she goes into labour and can't perform, than that's the end of the road. Nobody can be given a free pass on the show, it just wouldn't be fair to do that," added Kian.
Kian's second act Shane McLaughlin may be grabbing far fewer headlines, but the former Westlife star is quietly confident that underdog Shane can sneak into the final.
"I would be cautious about ruling Shane out, he has a huge fan base," Kian told the Herald.