THE X Factor has been an emotional roller coaster for The Dennis Sisters.

The Tewantin songbirds Briannah and Tiana, who are currently studying at Gympie's Australian Institute of Country Music, went from the high of their audition for the reality singing show to the low of not surviving tonight's three-seat challenge.

The sisters, aged 16 and 17, brought judge Guy Sebastian to tears with their rendition of Vance Joy's Fire and the Flood.

"I was fighting back tears because you guys are sisters and I think I just loving watching you guys hold each other up," Sebastian said.

But their mentor Iggy Azalea wasn't convinced.

"Although I love the sweetness and I love the connection I don't know if this was different enough from IndiElla to warrant me swapping (you for them)," she said.

But there's still hope for the duo with underdog judge Mel B taking her pick from the eliminated singers for her fourth team. The former Spice Girl will reveal which three singers or acts she has chosen on Sunday.

"When they told us it wasn't over yet and that they were in the process of telling everyone and waiting for a call back (from Mel B) we flipped," Tiana said. "We went from disappointed to hopeful."

Whether or not they get a second chance on Sunday, the sisters say they will push ahead with their music.

"Our plan is to keep writing, learning and improving. We're aiming to hopefully record an EP soon," Briannah said.

The Dennis Sisters will also travel to Tamworth early next year to perform at the town's long-running country music festival.

The X Factor continues tomorrow night on Channel 7.