The Roots - Late-night success after a move from hip-hop to house music

The Roots' regular gig as resident band on a US chat-show has given the veterans new impetus, their co-leader tells Ian Burrell

Ahmir Thompson, aka Questlove, is talking on the sixth floor of New York City's GE Building, aka 30 Rock, home of the NBC television network and inspiration for Tina Fey's hit television comedy of the same name. Thompson and his band The Roots have settled in at the Art Deco tower, where they are the house band on the chat show Late Night with Jimmy Fallon, NBC's successor to Conan O'Brien and David Letterman.

The Late Night theme tune is "Here I Come", from The Roots' album Game Theory, and at the top of each show they are introduced to the audience as "the legendary Roots crew". Incorporating jazz and other genres in their compositions, The Roots' musicianship is widely held to be peerless in hip-hop.

The Philadelphia group will make their first appearance in Britain in two years tonight, returning to the city where they formerly lived, London. "Philly has always been home and our second home is now 30 Rock, that's the address where we spend 12 hours a day," says Thompson. "But without London this would have been a strange journey. We have extreme loyalty to the place where we got our beginnings."

When he is in the British capital he always goes back "by cab or by Tube" for a look at the flat the band shared in Queen's Crescent, in north London's Kentish Town. "The first thing I do is jump on the Northern Line, get off at Camden and just walk. Sometimes I even go to the fish and chip spot that we used to visit e-ver-y night."

It was during that year in London between the summers of 1994 and 1995 that The Roots, visiting clubs such as central London's Iceni, developed tastes for eclectic musical nights out. When they returned to America they took the idea with them, supporting Philadelphia's Black Lily showcase at the Five Spot club, which gave a platform for female artists such as Jill Scott and Jaguar Wright, who have become stars. Today the band are behind several festivals in their home city, hosting The Roots Picnic and headlining Philadelphia's Fourth of July celebrations.

Thompson, a drummer and producer, credits London for the inspiration. "All of those nights at that club, Iceni, we had never seen that before. You had one floor with one type of music, another floor for another type of music and a third floor for a jam session, games and socialising. We came home and said, 'we're going to do the same thing we saw in London,' and sure enough it worked," he says.

"And then the idea of festivals, of taking a whole bunch of music and having them all on one stage. America is now just getting used to the idea of festivals and we now [have] three in Philadelphia. We took what we learned and just ran with it."

The Roots came to London at a moment when they were unsure if their fledgling musical careers were going to work out. Thompson was aged 22 and Tariq "Black Thought" Trotter, the group's rapper, was a year younger.

"We ran away from home and those were exciting and risky times," says Thompson, now 40 and one of hip-hop's most distinctive figures. "We had the fear that we were going to get dropped from our label and we thought we better take matters into our own hands."

Stepping into another environment helped the band to develop, and today they are working on their 13th album after a career of almost unparalleled longevity in hip-hop.

Most rappers, says Thompson, simply live in the present. He has a different view. "The thing that separates us from them is that we have always operated from the position of, 'how can we still do this'... it used to be five years from now but now it's 'how can we still do this 20 years from now?'"

His awareness of the importance of a long career path was enhanced by the harrowing sight of a once great rapper gathering his luggage in an airport terminal, and of another collecting up the chairs at the end of an awards show.

The new album will be titled Undun and Thompson says it is like nothing The Roots have made before.

"We are trying to toy with the idea of telling someone's story, a sort of a running narrative of a particular character from beginning to end. This is going to be our first concept album."

To add to the narrative feel, each of the 13 tracks will have its own video. "We are going to give each song to a particular short-film director that we like and see what concepts they come up with."

This segmentation of the story is part of a process known to The Roots by the name of another favourite film director. "Quentin Tarantino's name is always used as a verb around these parts. We say, 'OK, we are going to Tarantino it'."

Black Thought is one of hip-hop's most intelligent lyricists. Thompson says that the group attempt to address political issues in a subtle manner by recounting "everyday" experiences, another reason the group stand a little apart from the mainstream.

"In hip-hop the protagonist is always this larger-than-life figure, but I think we are definitely more comfortable with telling the everyday-man story. The thing is how to keep a character interesting that isn't a drug lord or isn't the richest guy in existence or a rebel to America."

The integration of so much visual imagery must be helped by being based full-time in a national television network, where the eight-strong band have had their dressing rooms – alongside the famous Studio 6B – turned into a rehearsal and recording space.

"We have never been in a more focused position," says Thompson. "We are putting in 10-15 hours every day to this record and you can clearly hear the results. There's a renewed vigour and energy to it that I haven't felt in a long time."

Next month he and Thompson will head to Paris for Afropicks, a live project that mixes hip-hop, jazz and Afrobeats and includes artists such as Macy Gray and the Nigerian drummer Tony Allen. The title is also a reference to the comb which Thompson usually wears in his giant Afro hairstyle. He is also an associate producer with the Broadway production of the Fela Kuti musical Fela!

Thompson refers to the Malcolm Gladwell best-seller Outliers: The Story of Success as a favourite text for underscoring the value of a strong work ethic. "It really speaks the truth, which is that if you practise you get results."

The Roots play Hammersmith Apollo, London (0843 221 0100) tonight