Prime Minister Stephen Harper will be among the dignitaries at tomorrow's memorial service for victims of the Lac-Megantic disaster.

The prime minister and Gov. Gen. David Johnston will be there with their spouses, as will Quebec Premier Pauline Marois and Maine Gov. Paul LePage.

The service will be held at 11 a.m. at Ste-Agnes Church.

The mass will be presided over by Luc Cyr, the archbishop of Sherbrooke.

Organizers have reserved 700 places in the 1,000-seat church for loved ones of the derailment victims. Remaining pew spots in the church have been set aside for locals, volunteers and dignitaries.

Two big-screen TVs will be set up outside the church and will broadcast the ceremony live.

An estimated 47 people were killed in the explosive July 6 train derailment, an event that has sparked several lawsuits, a police criminal investigation and a probe by federal transportation-safety officials.

The federal government has promised $60 million for emergency assistance and longer-term reconstruction help for the town. It has also revamped some rules on train transport, following the advice of the federal Transportation Safety Board.

It will be Harper's second visit to Lac-Megantic since the tragedy. In his first visit, he compared the devastated downtown to a "war zone."