The baby-faced wunderkind who has written the first words Barack Obama will deliver as President is poised to make history as the youngest person ever to write an inaugural address.

Jon Favreau, 27, has spent the last two months working for up to 16 hours a day on the speech in locations all over Washington, from the Penn Quarter Starbucks to his new, still-unfurnished apartment in the city’s upmarket Dupont Circle.

As the day approaches, he has found himself writing until 2 or 3am, fuelled by double espresso shots and Red Bull. A team of assistants are on hand to furnish him with material, from research on key moments of crisis in American history to the collected speeches of former presidents.

A cult has grown up around new the chief presidential speechwriter since he penned the Iowa victory speech that launched Mr Obama towards the White House.

His boyish good looks have not hurt, nor has the emergence of an unfortunate Facebook photograph showing him drunkenly groping a cardboard cut-out of the new Secretary of State, Hillary Clinton, at a Thanksgiving party.

What also has Washingtonians swooning is his way with words, his effortless blending of his master’s voice with his own almost musical ear. He wrote the catchphrase “Yes We Can”, and he will be relied upon to come up with the most apposite, least-expected Lincoln quotation to frame Mr Obama’s hopes for America’s future.

Mr Favreau — or “Favs” as he is known to friends — was barely out of college and working as a speechwriter for John Kerry when he met Mr Obama backstage at the 2004 Democratic Convention. The Illinois senator was running over his lines when Mr Favreau impudently interrupted him to suggest a rhythmical rewrite. Mr Obama was astonished - and hooked.

Only a handful of aides have spent more time with Mr Obama since. The pair spent hours “just hanging out” on the campaign trail as Mr Favreau absorbed the candidate’s ideas and language.

“Barack trusts him,” said David Axelrod, Mr Obama’s top adviser, “and Barack doesn’t trust too many folks with that - the notion of surrendering that much authority over his own words.”

Come the day, Mr Favreau will swap his jeans and sweater uniform for a formal suit and take up an office in the West Wing as head of a White House speechwriting team with a dozen senior writers.

It will be quite a change of pace. It will also be his last job in politics — or so he has claimed. “Anything else would be anticlimactic,” he said.

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