Jonathan Firth is not a happy man. The 34-year-old brother of Bridget Jones star Colin sits in a Victorian leather armchair while the photographer snaps away for the photo on the cover of this magazine. And he looks like he'd rather be anywhere but here. It's something of a relief, then, that once the shots have been taken, Jon's face breaks into a smile and he visibly relaxes. Until he's asked a question about his more famous sibling. 'I'm not going there. Sorry,' he says. 'I've just decided that I've said everything I've got to say about him and I really don't have anything to add.' 

It's a hard subject to avoid. There's a definite family resemblance, but Jon looks like a more approachable version of Colin. Surely the fact that his older brother has made the leap from jobbing actor to film star must be intimidating? 

'You've got to be philosophical about it,' Jon shrugs. 'Success is comparative and there's always going to be someone more successful than you. Of course, you look at people and think "Why can't I?", but that way madness lies. 

'Everything I do gets described as a big break and I don't believe in the concept. When I first started getting big TV jobs I thought each one would be my big break, but I've got wiser and I've seen what's happened to my ontemporaries. Ninety per cent of successful actors get that "What am I going to do next?" feeling after every job.' 

Such level-headedness is not in evidence when the conversation turns to TV show Big Brother. 'I haven't seen Big Brother because it really annoys me,' says Jon. 'The first episode of likeness of Stone [the thriller Jon starred in last year] was screened on the final eviction night of the first series, so there was no competition. I was so frustrated with the BBC, they mayas well have just burnt £2m, just got together a big stack of money and burnt it. If they'd filmed that they would probably have got more viewers. I was really, really angry.' 

Going down in history 

Playing a 19th cenlury aristocrat has worked for one Firth brother, so perhaps playing Prince I Albert will propel Jon to that much sought-ofter I next level. Victoria and Albert is the latest Bank ~ Holiday period piece from the Beeb, but rather than focusing on an ageing Queen Victoria, this drama traces the love story between the young Queen and her beloved husband from their wedding to Albert's premature death. 

Playing the part of the German prince proved to be quite a challenge for Jon. ' All I really knew about Albert was that he was German and he died young,' he admits. 'He crops up in Blackadder and all that stuff, but I didn't even have a really clear idea of what he looked like. This is a man who Victoria was so deeply in love with that she mourned his death for the rest of her life. Yet we know nothing about the guy so that was really interesting.' 

In good company 

Jon also faced the challenge of being made-up to look like the fast-oging prince. The official reason for Albert's death was typhoid, but by the time he died at the age of 42 he was riddled with disease. 'Tuberculosis, plus various other ailments . of his bowels and intestines. You name it, he had it,' explains Jonathan. 'He aged incredibly fast. When he was 40 he looked like he was 60--it was astonishing. Victoria even mentioned it in her diaries because she just couldn't understand it. He filled out to an extraordinary degree and he lost most of his hair -the front of my head had to be shaved to achieve the receding look.' 

Spending so much time in the make-up trailer offered Jonathan the chance to bump into many of the show's cast. 'I walked into the trailer and realised I was the only actor in there that didn't have a knighthood, which was interesting!' 

The line-up for Victoria and Albert also includes Sir Nigel Hawthorne, Sir Peter Ustinov, Patrick Malahide and David Suchet, as well as The Savages star Victoria Hamilton who plays the young Queen. It's rumoured that things get a bit raunchy between the two leads, but the suggestion is met with a snort of derision. 

'It's all pre-watershed stuff,' says Jonathan. 'There is a wedding-night scene because the writers felt that this was obviously a passionate relationship, judging by the number of children the royal couple had in such a short space of time. It would be more glaring by its absence, but it's romantic rather than raunchy.' 

Hopes of another Firth sex symbol dashed, we move on to the dangers of typecasting. Has he fallen foul of our passion for the period piece? 

'I do spend an awful lot of time in the 19th century,' admits the star who has already graced our screens in the period dramas Middlemarch and Far From the Madding Crowd. 'But I'm not whining about that because it's better to be known for something than not to be known at all.' 

But if recent internet gossip is to be believed, Jon will soon be visiting a galaxy far, far away to take the role of Admiral Piett in Star Wars Episodes II and III. 'Well that's news to me,' he says. 'Really? Fantastic! I'm completely available and open to offers. I remember my uncle taking me and my cousins to see the original Star Wars. I lived in a rural area and there wasn't a cinema for 10 miles, so it was a big deal for me. I'd have to do it just for my 10-year-old former self!' 

Such excitement is a glimpse into a side of Jonathan you don't get to see very often. With any luck, the future will see him donning the breeches less often. And, casting directors willing, maybe a few swings of a light sabre will take him out of his elder brother's shadow once and for all. 

Victoria and Albert, BBCI, Sunday, 7pm; Monday, 6.30pm