Kelly, who has been out of action since January due to a hamstring strain, comes in on the right wing to replace recent signing Brian Carney, while O'Driscoll has recovered from the rib injury he picked up in Ireland's Six Nations win over Italy to be listed in the second row.
Carney, Eoghan Hickey, Tomas O'Leary, Eugene McGovern, Tony Buckley, Donnacha Ryan, Shane O'Connor, Tim McGann and John O'Sullivan have been dropped from the team that beat Ulster with Ireland internationals Kelly, Ronan O'Gara, Peter Stringer, Marcus Horan, John Hayes, Donncha O'Callaghan, O'Driscoll, David Wallace and Denis Leamy all returning.
O'Gara will captain the province, in the absence of lock Paul O'Connell (thumb).
Former skipper Anthony Foley is vying with the on-form John O'Sullivan for a place on the replacements. If Foley is selected and gets some game-time, he will take his Heineken Cup appearances record to 80 caps.
In all, Kidney has made four changes in personnel to the Munster side that went down 13-6 to Leicester in their final pool match in January. Three of those alterations are enforced with Shaun Payne, Barry Murphy and O'Connell out injured - Christian Cullen, Trevor Halstead and Alan Quinlan replace them - while Jerry Flannery has been preferred to Frankie Sheahan at hooker.
Tomorrow will mark Flannery's first European start since last May's final in Cardiff.
MUNSTER (v Llanelli Scarlets): Christian Cullen; John Kelly, Lifeimi Mafi, Trevor Halstead, Ian Dowling; Ronan O'Gara (capt), Peter Stringer; Marcus Horan, Jerry Flannery, John Hayes, Donncha O'Callaghan, Mick O'Driscoll, Alan Quinlan, David Wallace, Denis Leamy.
Replacements: Frankie Sheahan, Federico Pucciariello, Donncha Ryan, Anthony Foley/John O'Sullivan, Tomas O'Leary, Jeremy Manning, Barry Murphy.