"We're just interrupting our medicine-swapping time," he says from home in England, when asked how he and Ben are feeling. He's in good spirits, despite the bug he's caught.
Fittingly, Cullum's third album, last year's Catching Tales, comes across as infectious and unpredictable as a spring flu. Tales expands upon the piano-driven, radio-friendly jazz of his 2003 breakthrough, Twentysomething, by incorporating more pop and hip-hop, a few tricks he learned while collaborating with artists like Pharrell Williams (check their duet "You Can Do It Too" on Williams' upcoming solo release) and Dan the Automator, who produced the album's first single, "Get Your Way."
"I love to make challenging and interesting music that uses jazz as a platform and a basis to improvise," Cullum says. "But I also like to give it the edge and hookiness and immediacy of almost like a pop record, because I don't think that's done that often and I don't think it's done successfully very often. I'm just trying to find this common ground between disparate styles, and it's a lot harder than you might think. At least," he laughs, "without sounding like elevator music."
It's a curious marriage, jazz and pop and now hip-hop, and it's ruffled a few feathers. Critics haven't exactly warmed to the latest album the way they did the last time around, often dissing his experimentations that (despite their disapproval) actually manage to make jazz relevant to a college crowd that hasn't given a damn about the genre for decades.
"I care deeply about jazz, and I know a great deal about it, but I also grew up loving and listening to pop music and rock music, electronic jazz and acid jazz, and really, my expertise lies more in this blending of style, because I have a lot of respect for pop," Cullum explains. "Often when a jazz musician will experiment with pop, it's through kind of kitsch or camp or some kind of pseudo-intellectual mood. With me, it's because I actually really love Madonna."
This need to push the limits and establish new boundaries for jazz, pop, and music in general is something he gleaned from one of his heroes, the great Herbie Hancock, who throughout his career has continually revolutionized the meaning of jazz.
"Herbie's one of the great musicians of all time, just in terms of technique alone," Cullum says. "One of the amazing things about Herbie, though, like his mentor Miles Davis, is he was just fearlessly mixing and experimenting with styles, through jazz to funk to rock to disco to dance to electronica. He's fearless, and he always does it with grace and amazing musicianship. I try to bring some of that fearlessness as every musician should to what I do too."
And that fearlessness is present in the backbeat-driven "Get Your Way," a stand-out track on an album littered with tracks begging for attention (like "Photograph" and "I'm Glad There Is You," both of which deserve a place in the next Richard Curtis Brit-comedy).
"The thing with 'Get Your Way' is that it's a blend of a lot of styles I like," he says. "I love hip-hop. There's not a rap in that song, but there's a hip-hop beat, and it's produced by a hip-hop producer a great one, Dan the Automator. It's got like a pop-hook chorus and has a jazz piano song in the middle. The lyrics are quite intelligent and suave like Cole Porter, but actually the song's about getting laid. It's all these paradoxes, pushes and pulls, and things I like.
"It might not be the most revolutionary thing in the world," he adds, "but it does up a lot of music I like in one song." Sounds like a fever worth catching.