The look on UK chat show host Michael Aspel's face is priceless.
It's 1990 and Ella Fitzgerald, jazz legend, first lady of song, has just told Aspel that she wants to record the theme tune from Aussie soap Neighbours.
"Ella Fitzgerald sings Neighbours. I can't ... " Aspel says, shaking his head, unable to process this information.
"I might have a hit with it," she tells him.
She might have, too. Ella Fitzgerald could do anything. She magicked base metal into gold — see her first hit, the nursery rhyme A-Tisket, A-Tasket. She made great songs greater (her Songbooks series recordings of Gershwin, Cole Porter et al). She played with the immortals and elevated them by her very presence: Duke Ellington, Count Basie and Frank Sinatra.
Few could keep up with her; Louis Armstrong could. He wasn't the first jazz musician but he was the first great one. The sounds that came from his trumpet weren't notes; they were joy with a key signature.
When the two got together, well ...
"They didn't get in each other's way, neither diminishes the other," says Australian trumpeter James Morrison, who leads an Ella and Louis celebration with the Auckland Philharmonia Orchestra this month.
Morrison remembers, as a 7-year-old, hearing Armstrong and loving the sound but getting annoyed when Louis sang. "Stop the singing and pick up the trumpet!"
Listening to Ella and Louis together made the budding instrumentalist appreciate jazz singing.
"It was the most influential example I had of two musicians with very strong voices working together and being greater than the sum of their parts."
The parts were exceptional. Armstrong can claim to be the most important of all jazz musicians. Forget the beaming middle-aged crooner of What a Wonderful World, his period of greatest achievement came 40 years earlier, as leader of the Hot Five and Hot Seven groups.
"Louis was an innovator," says Morrison. "If you listen to what was around prior to him and while he was playing in the early part of his career, he was out on the front edge."
In the mid-1920s Armstrong laid the template for New Orleans jazz. His recordings from that period are short and sharp bursts of energy, with extended improvised solos and scat singing that echoed his trumpet playing.
If Louis popularised scat, Ella perfected it. She could do a good Armstrong impersonation, too. In a famous recording of Mack the Knife, she forgets the words and makes up new ones on the spot, variously mimicking Louis's gravelly voice and scatting like a trumpeter. That performance earned Fitzgerald a Grammy.
Remarkably, given their importance as a duo, Ella and Louis recorded just a handful of singles and three albums together, Ella and Louis (1956), Ella and Louis Again (1957) and Porgy and Bess (1959). The first two were with a small group led by Oscar Peterson, while Porgy and Bess was a full orchestral number, with arrangements by Russ Garcia. (In the late 1960s Garcia moved to New Zealand, living in Kerikeri until his death in 2011, aged 95.)
These albums are fun and swing hard — Again 's Stompin' at the Savoy is unhinged — but Ella and Louis's music together almost belongs to an earlier era. When Ella and Louis was released, Little Richard and Chuck Berry had enjoyed their first hits and Elvis Presley's debut album changed music forever. Even in jazz, the Fitzgerald/Armstrong collaborations were throwbacks.
Around the same time the pair released their selections from Gershwin's folk opera — itself a quarter-century old by then — Miles Davis went modal with Kind of Blue and free jazz pioneer Ornette Coleman made his intentions clear with the chaotic The Shape of Jazz to Come.
With everything else happening in music at that time, who would want a bunch of dusty old standards? Everyone. Ella and Louis immediately hit number one on Billboard's jazz chart and went top 10 in the pop vocal list. The three records remain among the best-selling jazz discs in history.
But then Ella and Louis were always intent on reaching as many people as possible. For Armstrong, in particular, it was a priority.
"My life has been my music, it's always come first," he said a few years before his death in 1971, "but the music ain't worth nothing if you can't lay it on the public. The main thing is to live for that audience, 'cause what you're there for is to please the people."
James Morrison has Armstrong's quote on the wall of his music academy in South Australia. "There are other reasons to play trumpet," Morrison says, "I just can't think of a better one."
What: A Celebration of Louis and Ella, with James Morrison and the APO
Where and when: ASB Theatre, Aotea Centre, Thursday, August 16