Ahmir "?uestlove" Thompson, drummer of the Grammy-winning band the Roots, said he was eagerly anticipating what may be America's biggest party of the year: the Philly Fourth of July Jam on the Parkway.

"I'm so ready for this to happen," he said Thursday as Mayor Nutter announced the lineup for the Independence Day event. "I can't wait."

Grammy-winning artists John Mayer and Ne-Yo are among the musicians who will rock with the Roots and an expected half-million spectators at the free concert celebrating the nation's birthday.

"It's definitely our favorite event of each year," said Roots rapper Tariq "Black Thought" Trotter.

"Thank Wawa for making this the No. 1 party in the United States of America," Nutter said. "You can celebrate it in other places, but there's no place like Philadelphia to celebrate the Fourth of July."

Jill Scott, a Philadelphia native and R&B artist, will also perform. Others in the lineup include Demi Lovato, Grace Potter, up-and-coming rap sensation J. Cole, and Ben Taylor, son of James Taylor and Carly Simon.

The Fourth of July Jam is part of the weeklong Welcome America festival. This year is the 20th anniversary.

The festival begins July 1 and ends July 7. Several educational programs will be unveiled during the week, including an exhibition at the National Constitution Center on the history of the hoagie. The signature Taste of Philadelphia food-sampling event will take place from July 5 to 7.

Wawa Inc., with more than 600 stores, is serving as Welcome America's title sponsor for the fourth year.

"Philadelphia is Wawa's hometown," said the company's president and CEO, Chris Gheysens. "This is free family fun."

Nutter announced the jam's lineup Thursday at the Top of the Tower high-rise in Center City, overlooking the Parkway Museums District, where the July Fourth concert will be held.

Anyone craving more music after Independence Day can spend July 6 at Penn's Landing and listen to the singer and songwriter Marsha Ambrosius. Formerly a member of the duo Floetry, Ambrosius penned "Butterflies" for Michael Jackson and other hits for artists such as Alicia Keys, Justin Timberlake, Jamie Foxx, and Nas.

Local natives Thompson and Trotter formed the Roots in 1987 in Philadelphia. Trotter said "it's a very proud moment" for the Roots to return to the Parkway as one of the headliners.