Cobain's widow Courtney Love has made the claim that Devlin is related to the deceased singer, saying that she "is a cousin of Kurt's ancestors from County Tyrone".
Following her revelation, NME contacted the Devlin family via a publicist for the singing competition to see if the link was valid.
The Devlin family said they were "completely unaware" of the connection, while Janet added: "I'm not aware of any family connection but it's pretty cool if that is the case."
Love attempted to get in contact with X Factor boss Simon Cowell last month, saying that she had the "perfect idea" for Devlin to cover a Nirvana track.
It was recently confirmed that Devlin topped the X Factor live show result for four consecutive weeks at the beginning of this year's competition.
Watch Janet Devlin perform 'Fix You' below: