At Harris' rally in Milwaukee, the campaign announced in the arena that the vice president will be broadcast into the DNC and that they want the crowd here to "bring the energy."

"I'm really going to need this energy when they broadcast this live, right?" said Jaliah Jefferson, Wisconsin deputy organizing director, Milwaukee. "VP Harris will be beamed into TVs all across the country."

"So when it's our moment, we need to get loud and leave no doubt that Wisconsin is going to send Kamala Harris and Tim Walz to the White House," she added.

Crowds have been waiting for hours to enter the Fiserv Forum -- where the RNC was held last month. The arena is packed with people and it's a party vibe. The music has been pumping loudly, people are dancing and waving their light-up wristbands. The bass in the music is so loud the floor is vibrating.

-ABC News' Selina Wang and Will McDuffie

Kamala Harris' stepson Cole Emhoff paid tribute to his father, second gentleman Doug Emhoff, and how the vice president became part of their blended family, in a video posted on social media ahead of Emoff's DNC speech tonight.

"In 2014, Kamala became Momala," Cole Emhoff said. "She took over Sunday night dinners and taught Doug how to actually cook."

"Our blended family wasn't used to politics or the spotlight, but when Kamala became senator, we were all excited to step up -- especially my dad," Cole Emoff added. "Then, Kamala became vice president. It felt like Doug was a bit out of place on Capitol Hill. I thought: 'What is my goofy dad doing here?'"

-ABC News' Fritz Farrow

The roll call for the DNC has begun.

State delegates will go in alphabetical order, with a DJ playing music related to each state.

Pennsylvania Gov. Josh Shapiro told ABC News Live Prime anchor Linsey Davis in an interview from the DNC that he is seeing "incredible enthusiasm" for the Harris-Walz campaign on the ground.

"Kamala Harris is showing up in communities that are oftentimes ignored and left behind," Shapiro said, adding that she's sending a message to Pennsylvanians that she cares about them.

"I think as this race progresses, you're going to continue to see real momentum on her part," he said.

6:53

Pennsylvania Gov. Josh Shapiro on Harris-Walz ticket

ABC News’ Linsey Davis speaks with Pennsylvania Gov. Josh Shapiro (D) about the importance of delivering the state for Harris-Walz and the momentum he sees on the ground.