Viewers flocked to the return of the latenight gabfests on Wednesday, giving Jay Leno, David Letterman, Conan O’Brien and Craig Ferguson season-high ratings among total viewers.

According to fast national Nielsen ratings (final numbers will be out next Tuesday), Leno’s “Tonight Show” averaged 7.2 million viewers — up 40% from the show’s season average, and its best showing since Dec. 8, 2006. It also repped Leno’s best Wednesday night viewership since Feb. 4, 2004. Leno’s adult 18-49 average was a 2.2 rating, up 41% from the season average.

Letterman’s “The Late Show” did nicely as well, averaging 5.5 million viewers. That’s “Late Show’s” best perf since Nov. 20, 2006, and up 34% from its season average. Letterman’s 1.7 rating in the adults 18-49 demo was the show’s best since May 17, and up 35% from its season average.

O’Brien pulled in 2.8 million viewers, his best since Feb. 13, up 36% over his season average. “Late Night” averaged a 1.2 rating in the adults 18-49 demo, up 42%.

Ferguson landed 2.2 million viewers, up 22% from season average and its best showing since May 10. “Late Late Show” averaged a 0.7 rating with adults 18-49 — up 14% from season averages, but not a season high.

With so much attention on the Leno vs. Letterman battle, ABC’s “Jimmy Kimmel Live” didn’t post season highs in its return, but it didn’t slump, either. Show matched its season averages with1.8 million viewers, and a 0.6 rating with adults 18-49.