Thank heavens the instantly likable Ms. Dickinson surfs the sometimes breathless language with ease, and if she’s a different physical type from the real-life Lucy, the actress compels attention in her own right and not simply because she has hitched a ride on a legend. You may resist the implicitly self-glorifying tone to an enterprise that, from the “I” of its title, puts Mr. Tannen first. And yet, “I Loved Lucy” features a leading lady in whose presence one can only kvell, to employ the same admiring Yiddishism used by Mr. Scott’s Lee (who explains the word for a London public).

Mr. Scott was seen on Broadway this time last year as a replacement cast member in “An American in Paris,” the dance-heavy musical whose original Broadway and London leading man, Robert Fairchild, recently turned toward iconic American material on an especially capacious London stage.

I’m referring to the BBC Proms concert staging a few weeks ago at the Royal Albert Hall of “Oklahoma!” It received two performances on Aug. 11; I was at the matinee. In a city that loves Rodgers and Hammerstein, this account of the pioneering 1943 show about frontier folk generated advance curiosity for the casting of Mr. Fairchild as the lanky young cowpoke, Will Parker. How would this performer fare away from the New York City Ballet, where he has made his formidable name? The short answer: exhilaratingly well, contributing a showstopping supporting turn that sometimes eclipsed the leading players. It helped that the Utah-born Mr. Fairchild was at home with the spoken twang of a show that defeated English cast members like Belinda Lang, in gratingly shrill voice as Aunt Eller.

But it was the footwork that elicited vociferous cheers from an audience already jazzed by the presence of the John Wilson Orchestra, whose British contribution to the American repertoire constitutes a special relationship all its own.

Not often, I imagine, has that second-act knees-up “The Farmer and the Cowman” received the whiplash physical brio that Mr. Fairchild brought to it, alongside a pleasing tenor that has only been strengthened by his experience singing Gershwin in three cities, starting in Paris in 2014. (Mr. Fairchild departed the London company of “An American in Paris” in June and will be seen in concert in “Brigadoon” at City Center in New York in November.)

It so happens that his West End castmate, David Seadon-Young, was part of “Oklahoma!” as well, playing a Jud Fry of fiercely brooding power before returning across town to his current tenure as Adam Hochberg, the resident narrator of “An American in Paris.” An American territory on the verge of statehood might seem miles away from a French capital in the aftermath of war, but here are two performers who make one eager to see where in the world they will take us next.