David Letterman (search), who was on vacation when Johnny Carson (search) passed away Jan. 23, returns tonight with a Carson-appreciation show and a long look at the impact the late "Tonight Show" (search) host had on his career.

Letterman has lined up former "Tonight Show" bandleader Doc Severinsen, who will perform, and Carson's former executive producer, Peter Lassally.

Letterman credits Carson, a fellow Midwesterner, with giving him his big break.

Dave guest-hosted for Carson on the "Tonight Show" before NBC — with a push from Johnny — named Letterman the host of "Late Night," which followed the "Tonight Show" at 12:30 a.m.

Carson appeared twice on "Late Show" after Letterman moved to CBS — but never appeared with Jay Leno on the "Tonight Show" after he retired in 1992.

Leno's tribute to Carson last Monday was a big ratings magnet, boosting the usual audience for the "Tonight Show" by more than 50 percent.

In fact, just about all the news and entertainment shows marking Johnny's passing — including Larry King's CNN talk show and a number of NBC specials — have been huge ratings getters.

Carson, 79, died from emphysema.