LOS ANGELES -- In no time, Nat Faxon and Dakota Johnson were tight.
That’s good, since they star as brother and sister on their new Fox comedy, "Ben and Kate."
Ben is a free spirit, a good-cheer gadfly blowing in and out of town without notice. Younger sister Kate is uptight, a bit shell-shocked by life, and no wonder: She’s a single mother struggling to raise her child on a shoestring.
What will happen when, after Ben’s latest drop-in, he decides to stick around, re-establish ties with Kate, play surrogate dad to her daughter, and even grow up a little himself?
To judge from the "Ben and Kate" pilot (airing today at 8:30 p.m. EDT), the result is funny, frenetic and -- bottom line -- familial.
"It was very natural," said Nat, thinking back to last spring when the pilot was shot. "It felt like Dakota and I had known each other a long time, rather than a few days."
"We have a -- is there a word for a sibling sort of relationship?" asked Dakota, who, pretending to consult her smartphone, then proposed: "Siblingry!"
"We are close enough now that Dakota feels it’s OK to say how long my ear hair is, out loud, to a large group of people," Nat stated. "THAT’S how comfortable we are!"
Co-starring with them on the series are Echo Kellum as Ben’s loopy pal and Lucy Punch as Kate’s hot-chick BFF. Maggie Elizabeth Jones plays Kate’s adorable daughter.
But the magic of "Ben and Kate" is the connection between Nat and Dakota, who, joined by a reporter at the Twentieth Century Fox lot for an interview in August, had been freshly reunited to resume the series grind.
The 36-year-old Nat, wearing chinos, polo shirt and a generously toothy smile, had come to "Ben and Kate" with credits including the films "The Babymakers" and "Bad Teacher" as well as a short-lived sitcom "Happy Hour."
He said he had auditioned for Ben "early, early on," then learned he had won the role on Feb. 27 -- one day after he collected an Oscar for co-writing the George Clooney film "The Descendants."
"I did NOT win an Oscar," countered Dakota, deadpan, "and I came in superlate."
She is the 22-year-old daughter of actors Don Johnson and Melanie Griffith who, building on her early modeling career, has appeared in films including "21 Jump Street" and "The Social Network."
"I got the ‘Ben and Kate’ script one night and met with everyone the next morning," she recalled. "They gave me 15 or 20 pages of sides to memorize. Then Nat and I read together, and it was awesome. That night they called and offered me the role: ‘And, by the way, can you be in rehearsal at noon tomorrow?’ So it all happened in like 24 hours."
Their instant "siblingry" is remarkable, as is their comic rapport, particularly since their backgrounds in comedy differ markedly.
"I never considered comedy until I auditioned for ‘The Five-Year Engagement,"’ Dakota said. That Judd Apatow comedy, released last spring, "was where I got my first taste of improv."
Nat, by contrast, spent a decade with the Groundlings improv troupe. But he doesn’t claim to have the upper hand being funny.
"It’s mostly innate," he told Dakota reassuringly. "You have the ability and the willingness to try different things, and that goes a long way."
"Ben and Kate" was created by Dana Fox, who based the show on her relationship with the real-life Ben Fox, her freewheeling brother.