It’s about to be lights-out at iO West, where funny folks have learned and performed Chicago-style improv in Los Angeles for more than 20 years.

Charna Halpern, owner of the theater as well as the original iO in Chicago, announced Tuesday on Twitter that the venue will shut down Feb. 24. The Chicago operation, based since 2014 at a multi-theater complex at 1501 N. Kingsbury, is unaffected.

“iO in Chicago is strong and I hope that everyone from my LA theater knows this’ll still be their home,” Halpern said in a statement to the comedy news site Splitsider.

A former student at iO Chicago, future TV actor and producer Paul Vaillancourt, opened iO West in 1997 as a performance and classroom space for Chicago transplants and for newcomers interested in the long-form improv style promoted by Halpern and her artistic partner, Del Close. The duo’s former students became the teachers at iO West.

iO West moved into its current space at 6366 Hollywood Blvd. in 2000. Halpern told Splitsider that audience and student numbers dwindled after a disreputable club moved in next door, and then bands began disrupting shows by rehearsing in the floor below.

The final show there, Halpern said, will be headlined by Beer Shark Mice, a group that includes Vaillancourt, David Koechner of “Superior Donuts” and Neil Flynn of “The Middle.” All male and all Chicago-trained, they have been performing at iO West off and on for years.

Chicago improv gospel will continue to be taught at the two Los Angeles theaters of the Upright Citizens Brigade, founded by the locally trained Amy Poehler (“Parks and Recreation”), Matt Walsh (“Veep”), Matt Besser and Ian Roberts.