Let there be light tonight.

Shortly before 6 p.m. Mayor Nutter and his wife, Lisa, will wrap up an hour-long celebration by flipping a switch to fire up 5,800 LEDs on the city's holiday tree, including 129 just on the five-pointed star.

Singers and performers from various shows will be part of the "Holiday Celebration and Treelighting Spectacular," starting about 5 p.m. at JFK Plaza (LOVE Park), amid the Christmas Village, with its 50 wooden booths.

The event was postponed from Wednesday because of the threat - and eventual actuality - of heavy rain.

Traditionally, a real tree was set up outside City Hall, but this year it's artificial (with 672 silver-and-red ornaments), and it's in the nearby park because of construction at Dilworth Plaza.

So the tree's a backdrop bonus these days for people posing for pictures in front of the LOVE sculpture.

Singing will be the Municipal Employees Choral Ensemble and the casts of two musicals in town this month and part of next - The Jersey Boys, playing at the Forrest Theatre, and The King & I, at the Walnut Street Threatre.

"Special appearances" will include the Mouse King from Pennsylvania Ballet's The Nutcracker, running all month at the Academy of Music, and characters from a movie based on Dr. Seuss' The Lorax that's set to be released in March.

Because of the LED lights, the tree will use about a quarter of the power of conventional lighting for a tree that size - about as much as a common household refrigerator would use, said spokesman Randy Giancaterino.

Sponsoring the event are Kindy's Factory Outlet of South Philadelphia and Kraft Macaroni and Cheese, which has been symbolized for more than a week by a giant yellow noodle with the words "You know you love it" at the corner of 15th Street and JFK Boulevard.