In England we are used to seeing the actress  Rose Byrne looking harassed in a power suit as her psycho b*tch boss,  played by 
Glenn  Close, plans yet more horrors for her to endure. But while Rose  awaits a decision on whether the 
Emmy-winning  legal drama Damages will run to a fourth season, she has been keeping  herself busy with a very different project. 
Get Him to the Greek  is the (more successful) follow-up to 
Forgetting Sarah Marshall,  in which 
Russell  Brand plays a washed-up rampaging old rocker. Byrne is his  girlfriend, Jackie Q, a model and singer with glitter teardrops and an  unfortunate line in obscene lyrics.
'I kept saying to Nick Stoller  [the director]: "Thank you for even auditioning me!" because I knew it  was quite a stretch. Jackie uses her sexuality and you can see that I'm  not like that at all,' says Rose, who is dressed today in a baggy grey  jumper. 'But it's liberating to play someone entirely different from who  you are.' 
Rose, 30, grew up in Balmain, a middle-class suburb of 
Sydney.  Home was a house full of antiques and not much technology. Her parents,  Jane, who works in the office of an inner-city Aboriginal primary  school, and Robin, a retired market researcher, are modern Luddites who  eschew gadgets such as mobile phones and microwaves, thus ensuring that  their four children are a creative lot: Lucy, in publishing; Alice, a  painter; George, a folk singer; and Rose, the youngest, who started  drama classes when she was eight. 'I was quite a shy child, quite timid,  and with acting I could disappear a little bit, be someone else,' she  explains. In fact, Rose was so quiet that at school her nickname was  'Mute' and a fear of clowns caused some anxiety when her father quit his  job to become a clown. 'My dad is nutty. He recently gave up being a  clown and is now a Tasmanian garlic farmer.'
At 13, Rose was  cast in the Australian movie    
Dallas Doll, opposite the comedian  Sandra Bernhard, which was followed by a 
Neighbours-style  soap, 
Echo Point. The show was not a success and was cancelled  after just three months. Subsequently Rose became 'a bit of a wild  child. I was climbing out of my window and sneaking off to raves by the  time I was 15.' She briefly moved to 
New  York at 19 to study acting at the Atlantic Theater Company, founded  by 
David  Mamet and 
William  H Macy, and that same year was in an Australian crime film called 
Two  Hands, which also starred a young 
Heath  Ledger. 'He was wonderful to work with – just a really spontaneous  and natural performer and a very warm-hearted person. He was very  enigmatic even then and he had a lot of energy. We were both kids really  and that film was a big turning point for me. He was just so talented.  To be honest, it's really hard talking about him. What happened was just  so tragic and sad.'
After a cameo as one of Princess Amidala's  comely handmaidens in 
Star Wars: Episode II – Attack of the Clones,  Rose had her breakthrough role in an adaptation of Dodie Smith's 
I  Capture the Castle, playing the lovely and love-sick Rose Mortmain.  It was this part that brought her to the attention of 
Brad  Pitt, who was searching for a Briseis for his Achilles in 2004's 
Troy.  Rose triumphed and spent most of the time in Achilles' tent waiting for  him to return from battle for their romantic interludes. In the film  Pitt had an extraordinary physique: 'All the boys in the film were  ripped,' says Rose. 'Brad, 
Orlando  Bloom and 
Eric  Bana. They were all on weird diets and eating chicken at nine in  the morning. Their bodies were like pieces of machinery. They belonged  in the 
Louvre.'
Rose  moved to 
London  shortly after 
Troy to film the 
BBC  mini-series Casanova, opposite 
Peter  O'Toole. She bought a terraced house in Hackney with her sister  Lucy and still professes a love for all things English. 'I used to hang  out in Dalston, and the 
Arcola  Theatre and Catch 22 in 
Shoreditch.  I loved it there, but could never compete with the hipsters. I went  back about a year ago and had a great time visiting all the old haunts. I  grew up on British comedy like 
Fawlty  Towers and I love 
Extras and 
The Office,  although 
The League of Gentlemen always makes me feel a bit  weird. I went to the 
Golden  Globes in January when 
Ricky  Gervais was presenting. The audience was a bit strange and serious  about it all, but I loved it and so did the Damages table. We were all  laughing at his jokes, but it was a hard room for him to work.'
Rose has lived in New York since she was cast as Ellen Parsons in 
Damages  four years ago, but her six-year relationship with Australian   actor-writer Brendan Cowell ended in January, even though he had moved   there to be with her. 'I was in a relationship for a very long time and,   to be honest, as far as the whole dating thing goes, I haven't even   gone there yet,' she says. She has a quiet social life and is happy to   have maintained her anonymity, which may be partly a result of a   tendency to suffer from panic attacks. 'For most of my life I have been a   slave to panic,' she says. This was particularly acute in her  twenties,  but a course in Sydney helped her address the problem and she  is, she  insists, much more relaxed now. 'I still get anxious, but when  I do I  know how to control it better. It is the main reason why I  don't go out  socialising too much. That's when my system goes down. If I  am in a  crowded place I immediately feel anxious.'     
High levels of anxiety  and paranoia pervade 
Damages, which is primarily concerned with  the warped relationship between Rose's character and her mentor and  nemesis Patty Hewes. 'I was very intimidated initially because Glenn's  such an amazing actress,' says Rose, 'but, in a way, it was OK for me to  be nervous because Ellen's very intimidated by Patty in the beginning.  But Glenn's wonderful and she's a friend now, which isn't always the  case on shows. Sometimes you can feel really alienated and isolated on  set, but that definitely wasn't what happened on 
Damages.'
Nor  was it the case on 
Get Him to the Greek. In fact, Rose felt so  at home on set that she abandoned all inhibitions and, in an  improvisational moment, did something that many have longed to do – she  gave Russell Brand a hard slap. 'We were filming an argument and Nick  Stoller likes actors to improvise, so I did,' says Rose, flushing with  embarrassment. 'Russell made me angry and I slapped him.' Rather  surprisingly, Brand did not respond well to this. 'Russell looked a bit  shocked and said how much it hurt because of his sensitive jaw.' 
  
In  fact, off-screen, Brand was unexpectedly sombre. 'Obviously, I'd heard a  lot about him beforehand but he wasn't a handful at all. He was very  contained and quiet and pensive. He's definitely eccentric and a  character, but he wasn't sleazy and I didn't know if I should have been  disappointed or not,' says Rose. Perhaps such gentlemanly behaviour can  be ascribed to the on-set presence of Brand's fiancée, the American  singer 
Katy  Perry (best known for her faux-risqué song 'I Kissed a Girl'). She  had a  small part in the movie that was eventually cut because, according  to  Brand, 'her acting was so atrocious that it ruined the film'. However, we do get to see Rose doing a perfect estuary accent – 'I lived   in Hackney for a while, so I was going for an East End accent,' she   says, 'and I used Russell as my barometer' – as well as dressing up as   Mary Magdalene in a kaftan, with Brand as baby Jesus lying in a manger   wrapped in a white sheet. 'We were doing a song called 'I Am Jesus'. My   biggest problem was trying not to laugh.'
All these high jinks  have given Rose a taste for slapstick. Her next role will be in a comedy  scripted by 
Saturday  Night Live's Kristen Wiig alongside 
Mad Men's Jon  Hamm and provisionally titled 
Bridesmaids. What would Patty  Hewes say?