VIDEO: Sneak Peek - Matt Long Guest Stars on ABC's PRIVATE PRACTICE

On the next episode of ABC's medical drama PRIVATE PRACTICE titled "You Don't Know What You've Got Till It's Gone," Sheldon fears the worst when a little girl goes missing from the ER; Addison and Jake have a disagreement about one of his patients; and a new doctor joins the team at Saint Ambrose. Meanwhile, Stephanie questions Sam about his past with Addison. The episode airs TUESDAY, OCTOBER 23 (10:00-11:00 p.m., ET) on the ABC Television Network. 

Mad Men's MATT LONG guest stars. Get a sneak peek below!

"Private Practice" stars Kate Walsh as Dr. Addison Forbes Montgomery, Benjamin Bratt as Dr. Jake Reilly, KaDee Strickland as Dr. Charlotte King, Paul Adelstein as Dr. Cooper Freedman, Brian Benben as Dr. ShelDon Wallace, Caterina Scorsone as Dr. Amelia Shepherd, and Griffin Gluck as Mason Warner, with Taye Diggs as Dr. Sam Bennett and Amy Brenneman as Dr. Violet Turner.

Guest starring MATT LONG as Dr. James Peterson, Tisha Campbell-Martin as Pam Reiter, Carter MacIntyre as Nick Calhoun, Justina Machado as Stephanie Kemp, Missy Yager as Megan Stewart, Charlie Hofheimer as Ron Nelson, Chryssie Whitehead as Dana Nelson and Steve Zissis as Todd Reiter.

"You Don't Know What You've Got Till It's Gone" was written by Fred Einesman and directed by Ann Kindberg.