The 'Heartbeat Song' hitmaker admitted the pair were close to working together on a song in the past but they were forced to reschedule.
Kelly told MTV News: "We almost got to work together, but I was pregnant and she had asked me to sing, I totally was down, but it just didn't work out.
"She was touring, I was super pregnant and not feeling well and it didn't work out this time, but it totally will... I love her; she's so sweet. Every time we see each other, she's always like, 'Kelly Clarkson, she's so nice, and so awesome, we're both Texans.'"
Meanwhile, Demi previously admitted that Kelly, 32, would be her "dream collaboration".
She tweeted: "Dream Collabs: Kelly Clarkson (duh), Eminem, Ed Sheeran, Marc Anthony, Christina Aguilera, Macklemore, Lil Wayne, Nicki Minaj, & Drake (sic)"
The 22-year-old singer also recently expanded on her reasons behind wanting to work on a track with Eminem.
She added: "I would love to work with Eminem actually... I can relate to him with being in recovery and things like that so I think we could make something awesome together."