Parents of young children are often spooked by the risks of last-minute Halloween costume shopping: wait too long and the costumes-of-the-moment may be all snapped up.

But Jesse Tyler Ferguson has learned that planning in advance has its own perils.

“I fell into that trap of buying Halloween costumes six weeks too early,” Ferguson told Page Six on Sunday night at the Broadway opening of “Sunset Boulevard” — a revival of the 1994 Andrew Lloyd Webber musical starring Nicole Scherzinger, formerly of the Pussycat Dolls.

The “Modern Family” alum — who shares sons Beckett, 4, and Sullivan, 1, with husband Justin Mikita — called his blunder a “rookie move.”

Ferguson explained that his original plan to “go as a family of skeletons” was foiled after his elder son changed his mind “a few times,” eventually settling on going as a tarantula.

“I just saw in our Amazon cart that Justin put in a tarantula costume because he’s the weak one,” the Emmy-nominated actor joked, adding that he and Mikita have revised their plans. They will go as Cole Escola and Conrad Ricamora, who play Mary Todd Lincoln and Abraham Lincoln, respectively, in the darkly comic Broadway play “Oh, Mary!”

Ferguson met his producer husband Mikita in West Hollywood more than a decade ago, when “Modern Family” was just beginning to take off. The two dated for two years before getting engaged in 2012.

That same year, the couple founded their Tie the Knot foundation to support groups working for marriage equality.

“It’s such a high-profile social issue right now,” Mikita told The Times during the early stages of the project, “that I think major corporations are tentative to get behind it.”

The next year, playwright Tony Kushner officiated Ferguson and Mikita’s 2013 wedding in downtown New York — one of the few places where same-sex marriage was legal at the time. (Ferguson later took on the officiant role himself, marrying his former co-star Sarah Hyland and “Bachelor in Paradise” star Wells Adams.)

Outside of Halloween planning, the “Dinner’s on Me With Jesse Tyler Ferguson” host told Page Six on Sunday that he’s also gearing up for his return to the stage.

“I’m going to be doing something on the West End which hasn’t been announced,” he said, “and I’m going to be doing Shakespeare in the Park next summer.”

Ferguson previously earned a Tony Award for his role in the 2022 Broadway revival of “Take Me Out.”