On the inclusion of O'Connell, Munster head coach Rob Penney said: "Paul wanted to be involved this weekend to keep building off the momentum of his successful Six Nations campaign with the Irish team.
"It shows the calibre of the player - he came to watch the team train on Tuesday and he wants to contribute against Treviso and secure more game-time ahead of a crucial period."
Damien Varley returns to captain the province for his first start since January as Penney makes 11 changes to the Munster team that was beaten by the Scarlets in round 16.
Earls starts on the right wing as one of four changes to the back-line with Felix Jones named at full-back, James Downey coming in to partner Casey Laulala in the centre and JJ Hanrahan wearing the number 10 jersey.
Johne Murphy keeps his place on the left wing with Duncan Williams staying as the starting scrum half.
Donnacha Ryan is the only forward to keep his place in the starting line-up with the Tipperary man moving from lock to blindside flanker.
Varley, James Cronin and John Ryan make up the front row. Billy Holland comes into the side to partner O'Connell in the second row.
Sean Dougall and Paddy Butler, who makes his first appearance since January after suffering a spinal concussion on club duty, are named in the back row with Ryan.
New Zealand hooker Quentin MacDonald was nominated for Munster's Heineken Cup squad yesterday and could make his debut off the bench with Ireland internationals David Kilcoyne and Stephen Archer completing the front row cover.
Record appearance holder Donncha O'Callaghan and CJ Stander are also named among the replacements.
Simon Zebo and Ian Keatley will be hoping to make an impact off the bench with Keatley looking to reach 500 points for Munster. The out-half has scored 497 points in his 66 appearances to date.
Gerry Hurley, who was also nominated for the Heineken Cup squad yesterday, provides the scrum half cover.
Match tickets are available to buy online here, and will also be on sale from the Mobile Ticket Office at Hassett's Cross tomorrow from 9am.
Ticket prices - Cat A Stand: €40; Cat B Stand: €30; Cat B Junior* Stand: €10; Terrace: €20; Terrace Junior*: €7; Family Terrace Pack: €40 (two adults and two juniors*). * Junior - Under-16s.
MUNSTER (v Benetton Treviso): Felix Jones; Keith Earls, Casey Laulala, James Downey, Johne Murphy; JJ Hanrahan, Duncan Williams; James Cronin, Damien Varley (capt), John Ryan, Billy Holland, Paul O'Connell, Donnacha Ryan, Sean Dougall, Paddy Butler.
Replacements: Quentin MacDonald, David Kilcoyne, Stephen Archer, Donncha O'Callaghan, CJ Stander, Gerry Hurley, Ian Keatley, Simon Zebo.