WHEN YOU place the bow on your cello, do you ever dream of playing with the fabled Philadelphia Orchestra cello section?

Well, now's your once-in-a-lifetime moment, open to beginners all the way to advanced musicians of all ages.

A free cello play-in will give that opportunity for your dream, or that of some youngster you know, at 6:30 p.m. Dec. 15, on Commonwealth Plaza inside the Kimmel Center.

First visit philorch.org/cello, choose your level: advanced/professional (Cello 1), intermediate/advanced (Cello 2), intermediate (Cello 3) or beginner (Cello 4); download the varied selections of music and register.

Seating is not guaranteed, but if you show up early with a folding music stand and rockstop, you have a good shot.

The audience is invited to this free, hour-long cello bash, and cellist Alisa Weilerstein (who will solo later in the Elgar Cello Concerto) and conductor Gianandrea Noseda will appear as well.

So how do you get to the Kimmel Center?

Practice, practice, practice.