He's one of the most popular Democrats and now Clinton will be called on to rally the party faithful.
"President Clinton has an economic record second to none. He's a very credible messenger," said Obama campaign manager Jim Messina.
The Obama campaign hopes Clinton's speech can pull in skeptical voters -- the ones who may not be sold on the president right now, but aren't quite ready to make the switch to Mitt Romney.
President Barack Obama and Clinton have had a rocky history. They famously clashed during the 2008 Democratic primary race. But with the lowest pre-convention popularity of any incumbent since the 1980s, the current president could really use the former's help.
Clinton currently stars in a new ad running in battleground states, which is his first of this election cycle. In the ad Clinton says, "President Obama has a plan to rebuild America from the ground up. We need to keep going with his plan."
Officials say Clinton's speech on Wednesday night will remind Americans of the thriving economy during his administration and how Democratic policies can bring back prosperity. But does the Obama campaign run a risk with that trip down memory lane?
"The danger for President Obama is that a lot of people might wish Bill Clinton were the president again because after all, the things were the whole lot better when he was president than they are today," said political analyst Cokie Roberts.
Chicago Mayor Rahm Emanuel, who worked in both the Clinton and Obama administrations disagrees.
"A former president who is very popular, who will talk and explain about the policies and the paralleled tracks that the two presidents have had, I think he can do nothing but help," said Emanuel.
Clinton is due on stage at 7:30 p.m. PT.
On Wednesday, Obama was scheduled to take the stage at the Carolina Panthers outdoor football stadium for the DNC finale. The arena holds 73,000 people, but now that event is cancelled and tens of thousands of people are being turned away. The weather is again disrupting the convention. On the heels of Hurricane Isaac causing problems for the Republicans to now, rain in North Carolina is scuttling plans for the president's outdoor appearance.
Frazier Scurry-Scott came all the way from Oakland to see the President accept his party's nomination. She got her pass for the Bank of America stadium. Like thousands of Obama supporters, she was counting on getting a seat in the open-air football arena.
"I'm one of the people fortunate enough to get a ticket from California, from Oakland. So I have my picture with President Obama's ticket and Vice President Biden's in my hands so I can go in tomorrow night," said Scurry-Scott.
However, the stadium tickets are no longer valid. Wednesday morning convention organizers said the forecasts for rain and lightening for Thursday night have forced them to scrap the stadium plans and instead, stay inside at the much smaller Time-Warner Arena.
"Oh, now you're saying, I have to get another ticket?" said Scurry-Scott.
That's the dilemma for many people. Tens of thousands of people are finding out their tickets to Thursday's big event, won't get them in to see the president.
Union City resident Harinder Kaur had five tickets and invited family and friends on Wednesday morning.
"I talked with them and they were so excited," said Kaur.
The Obama campaign had been giving out stadium tickets to campaign volunteers who now can't get in.
In talking with some Democrats, not all of them are up for a debate with the Republicans this fall. ABC7 had a sit-down interview with Sen. Dianne Feinstein, D-Calif., who is running for reelection this year and when we were in Tampa at the Republican convention, I spoke with her challenger about Feinstein's refusal to debate.
Feinstein's challenger, Elizabeth Emken, R-Calif., said last week, "You know, I'll give you a quote from the L.A. Times. The L.A. Times said, 'Nothing says entrenched incumbent like a 42-year politician who won't debate their challenger.
Matthews: I got to ask you about Elizabeth Emken. She wants to debate you. The L.A. Times came out and said you ought to debate her.
Feinstein: I'm running my own campaign.
Matthews: Is there anything more you can add to that?
Feinstein: I did a large event in Modesto, did three or four meetings, I've been to Southern California's and that's what I'll continue to do.
Matthews: Wouldn't it be better for the voters to hear both sides?
Feinstein: Thank you very much.
Feinstein did not like that question and does not intend to debate Emken.
Democratic National Convention live coverage
ABC News is providing live coverage of the convention and we'll be streaming it here live from 4 p.m. - 8:30 p.m. Tuesday through Thursday.
Weeklong local ABC7 News coverage
ABC7 News political reporter Mark Matthews will be reporting from Charlotte all this week and you can follow along on Twitter at @MatthewsABC7 or on Facebook for instant updates.
Political stories covered this week:
- First lady strikes personal chord in DNC speech
- Women shine in spotlight at DNC
- Thora Birch talks about being a delegate
- Michelle Obama will take DNC stage
- App helps separate fact from fiction in ads