The match will take place inside the Cell.
As noted, it's believed that the second Cell match will see Sasha Banks challenge RAW Women's Champion Becky Lynch, but that hasn't been confirmed.
Rollins confirmed the Cell match with The Fiend during the opening segment of tonight's RAW, which saw Wyatt interrupt from his Firefly Funhouse.
WWE Hell In a Cell takes place on October 6 from the Golden1 Center in Sacramento, California.
Below are a few shots from tonight's opening segment on RAW:
WWE (@WWE) September 17, 2019