DAR ES SALAAM, Tanzania - This is unprecedented: two U.S. presidents will make a joint public appearance in Africa Tuesday.

Former President George W. Bush will join President Obama in the morning at a wreath-laying ceremony at the U.S. Embassy in Dar es Salaam, Tanzania, to honor the victims of the 1998 bombing there, White House Press Secretary Jay Carney said today.

The event will be at 10 a.m. local time, 3 a.m. ET.

First ladies Michelle Obama and Laura Bush will also be appearing together on stage here at a First Ladies Summit hosted by Laura Bush. That joint appearance will be moderated by ABC News' Cokie Roberts.

Neither George W. Bush nor Obama is expected to speak at the event.

Obama has yet to shape a policy legacy for Africa comparable to that of his predecessor and he has been criticized for the perception that he has done too little for the continent.

Obama told reporters Monday that George W. Bush deserves "enormous credit" for his foreign policy aid programs, like PEPFAR, the President's Emergency Plan for AIDS Relief.

"This is one of his crowning achievements," Obama told ABC News' Jonathan Karl. "Because of the commitment of the Bush administration and the American people, millions of people's lives have been saved.

"There has been some suggestion that somehow, we've reduced our commitment there. The fact of the matter is, is that we are serving four times the number of people today than we were when PEPFAR first began. But because we've gotten better at it and more efficient at it, we're doing it at reduced cost," he added.

In shaping his own legacy, Obama has been touting his administration's plans to promote trade with African economies, boost private investment and increase access to electricity.

"Throughout Africa, we are looking at a new model that's based not just on aid and assistance but on trade and partnership," he said.

"What we want to do is use whatever monies that we're providing to build capacity. So we don't want to just provide the medicine; we want to help build the health infrastructures that allow Tanzanians to improve their overall health systems. We don't want to just provide food; we want to increase food self-sufficiency," he said.