The street is wide, quiet and tree-lined, with ridiculously steep steps at one end and a chaotic crossroads at the other. Several old men sit outside a bar on plastic chairs, contemplating the world in silence as they absorb the intense early-morning heat. Through a heavy wooden door, up four flights of stairs, there is the screenwriter, actor and director Gianni Di Gregorio on the landing, bowing slightly as he welcomes me into his flat.
He looks exactly as he does in the wonderful low-budget film Mid-August Lunch, the 2009 arthouse hit in which he cast himself as an unemployed bachelor whose life is dedicated to looking after his 90-year-old widowed mother. It's crazy to think that the film almost didn't get made. He wrote it in 2000 but no one would fund it. Finally, after Di Gregorio co-wrote the script for the brilliant Neapolitan mobster film Gomorrah, its director, Matteo Garrone, offered to produce it.
Di Gregorio ushers me into the simple, sparse kitchen, makes a pot of strong black coffee and sits down to build the first of many roll-ups. This family flat in the old Roman district of Trastevere is where he shot Mid-August Lunch, so the kitchen is oddly familiar. As I absorb my surroundings – the clutter of pots, the simple wooden table, the balcony with colourful geraniums and pots of green herbs – Di Gregorio fusses. He asks if I mind him smoking, if the nearby building work is too noisy. He is as charming and funny as his films, his fast, animated conversation punctuated by roars of throaty laughter.
In his new film The Salt of Life, Di Gregorio returns as a married man with a student daughter (played by his real daughter Teresa). He is still looking after his demanding mother – played once more by the formidable Valeria De Franciscis Bendoni – but she's living in a large art-filled house somewhere in Rome and Di Gregorio's main preoccupation is his increasing invisibility to women.
Di Gregorio tells me about his childhood in Trastevere. He grew up an only child in this very flat with a demanding teacher mother and an austere military father. By the age of six he would escape his bourgeois background by wandering around Trastevere, spending all day in the cinema or finding big families to eat with. He sounds like the boy in De Sica's Bicycle Thieves. "Yes! No! Not quite," he says. "Trastevere was very calm then. I grew up among the working class, but I always came home at night."
Trastevere has changed almost beyond recognition since Di Gregorio's childhood. On the west bank of the Tiber, opposite the Campo de' Fiori and just south of the Vatican, Trastevere was for centuries a working-class quarter populated by immigrants. Now the same labyrinth of cobbled streets and stunning squares is peaceful by day and chaotic by night as the endless bars and restaurants fill up with excitable young Romans and tourists. Popular though Trastevere is, there remains something special about it. "It has become so commercial and touristy and yet," Di Gregorio sucks hard on his roll-up, "its heart doesn't change. Something of its spirit stays. I think it has a working-class soul. I will always feel Trasteverino first and Romano second."
He offers to take me for a tour in his 40-year-old Fiat 500. He greets the inert men in the bar and unlocks the little car, a beautiful sky-blue relic with no suspension and no safety belts. What the hell; for me it's the equivalent of being shown around Manhattan by Woody Allen. It's noisy and scorching hot with the fabric roof folded back.
I ask why he doesn't have a more modern car. "I do. But my wife and daughters use it," he laughs as loud as the engine. "I'm very similar to the Gianni in my films. We certainly have the same weakness in terms of allowing ourselves to be bossed around by women."
We drive – surprisingly fast – up the steep hill that runs past the Fontana dell'Acqua Paola and see tourists dipping their feet in the cool blue water. "For me this is one of the most beautiful fountains in Rome. And you can see the city from here," he says, waving his hand to the right. But the better view is round the corner, at the top of the Janiculum Hill. It's not one of the original seven hills of Rome, but with its imposing statue of Garibaldi astride a horse, it's a great place to stare across the Tiber to the city.
We whizz past the thick, imposing walls of the Vatican, along the Tiber and over the river. We bump along the cobblestones, past the Forum, Palatine and Circus Maximus. We stare at the Colosseum. Di Gregorio gives me a rambling history lesson while trying to roll yet another cigarette and navigate the traffic. It's fun, but I'm relieved when he suggests returning to Trastevere. He heads for the east of Viale Trastevere, which is much quieter and less touristy, and parks outside the church of Santa Cecilia. It's a magical place with a tragic story: Cecilia was condemned to a slow, agonising death for confessing her Christian beliefs.
Inside it's empty, cool and quiet. Di Gregorio whispers incredibly loudly, which prompts a fit of giggles; there's something about him that makes you want to misbehave. He leads me to the basement to see the remains of an ancient Roman house (the singing gallery above the nave of the church is shut) and we wonder why none of the relics are protected. "It would be very easy to take a piece of history home," he jokes.
Outside, the sun is high in the sky and we stand in the shade for a while. The absolute stillness is interrupted by a Vespa buzzing past and then a young man approaches, saying: "Complimenti" – congratulations. He raves at length about Mid-August Lunch and Di Gregorio smiles, bowing slightly.
Gianni Di Gregorio's The Salt of Life is now showing in cinemas nationwide
Essentials
EasyJet (easyjet.com) flies from London Gatwick to Rome from £39.99 one way. Stay in the heart of Trastevere at the Hotel Santa Maria (hotelsantamaria.info), which has doubles from €90. Gianni Di Gregorio also recommends, "for the best pizza in town", Pizzeria Ai Marmi (53-59 Viale Trastevere). Da Augusto (15 Piazza de' Renzi) is a genuine, old-fashioned trattoria experience. Gianni says: "It's like la nonna used to cook at home: two first courses and three second courses from which to choose. You can find film directors, writers and teenagers eating good, cheap food." He also raves about Roma Sparita (Piazza Santa Cecilia; 00 39 6 580 0757, romasparita.com) and so does Anthony Bourdain, whose speciality is the simple but delicious tagliolini al cacio e pepe – pasta with pecorino and fresh black pepper. For a bar that still has the spirit of old Trastevere, top of Di Gregorio's list is Bar San Calisto (Piazza San Calisto, 00 39 6 589 5670). Known by locals as Sanca, it's far from posh but is cheap and lively. Di Gregorio calls it molto povero, suggesting that, unlike some of the flashier bars nearby, it hasn't deserted its working-class roots.
