Grammy Award-winning hip-hop group the Roots have announced that their fourth annual Roots Picnic will be held on Saturday, June 4. The headliners for the daylong mini-music festival are NYC rap veteran Nas and Wiz Khalifa.

This year's picnic will be held at Festival Pier at Penn's Landing in Philadelphia. The event's bill is loaded with its usual eclectic mix of acts, spanning multiple genres, including [article id="1657863"]Best New Artist Grammy Award winner Esperanza Spalding[/article]. Other artists scheduled to perform include folk artist Ariel Pink, electronic/pop band Little Dragon, and rappers Mac Miller and Yelawolf. Special and surprise guests are sure to be added as June 4 approaches, and many of the acts (such as Nas and Spalding) will receive their musical accompaniment from the Roots.

In addition to holding down a regular gig as the resident band for "Late Night With Jimmy Fallon," the legendary [article id="1648638"]Roots[/article] crew have maintained their recording career and perform concerts regularly. Led by drummer Ahmir "?uestlove" Thompson and MC Tariq "Black Thought" Trotter, they recently held their annual star-studded [article id="1657826"]Pre-Grammy Jam Session[/article] in Hollywood. Their collaborative album with R&B singer John Legend, Wake Up! was nominated for five Grammy Awards this year, winning three for Best Traditional R&B Vocal Performance, Best R&B Song and Best R&B Vocal Album. The Roots' 11th album, How I Got Over, was also nominated, for Best Rap Album.

Tickets for the Roots Picnic go on sale Friday, March 4, at 10 a.m. via Live Nation and Ticketmaster.