Caroline Morahan isn't the first to emigrate from Ireland this year, and she certainly won't be the last. She's done with here, for the time being. She's done with Irish TV and the Caroline Morahan that we know. For the time being. "What am I waiting for? This isn't a dress rehearsal, this is my life," she asks, somewhat rhetorically, somewhat emphatically, about her next move. Morahan is moving to LA to hopefully become an actress, or at least learn a hell of a lot in the process.

There is, of course, a certain cynicism invited by the phrase "but what I really want to do is act". It's an uttering that's generally met with rolled eyes the world over, from waitresses cajoling scriptwriters, to models expanding on their CVs, to pop stars taking ill-advised diversions. TV presenters? Not so much. But of course Morahan spent a chunk of her childhood in Fair City, and did a stint on stage with I, Keano after RTé's Off The Rails franchise was paid forward to Brendan Courtney and Sonya Lennon. Right now she's in "the visa process" and, come April, she wants to be chilling on Sunset Boulevard with her boyfriend, and hoping that it will become the boulevard of made dreams, not broken ones.

In a suite in a city centre hotel, myself and the Sunday Tribune photographer have spent a while watching Oscar news on the flat-screen TV (LA seems to be in the air today) and playing with the coffee machine. Caroline comes in looking quite radiant for someone who has been up since early morning. Outside, Ireland's pretend spring is lurking amongst the clouds, occasionally spurting drizzle on the top-floor balcony where Morahan will wait in the chill for her photograph to be taken in a cute black dress sprinkled with tiny white butterflies, and comment favourably on the smell of Guinness in the air from the pluming flues down on Thomas Street.

"Does anyone have the back of an earring?" Some of her bling has fallen out, but the make-up artist instructs her to go with just one earring. "Very Angelina," she says, a remark that makes Morahan smirk. There's a sort of collective flashback to when Morahan once compared herself to Jolie, something she was slagged relentlessly over, because Irish people aren't meant to have such notions. You sense that Morahan isn't into notions; she's into ambition, drive. And really, you have to hand it to her. She could very easily sit on her ass out in Montrose for the rest of her career picking up gigs here and there. Instead, she's taking a rather large risk. And there's probably no better time to do it, in a year that has already been typified by unbelievable flux.

For the last couple of years, she's really missed acting. She seems to indicate that TV has sort of got in the way of this, her new – or dormant – ambition. "Doing Off The Rails for as long as I did, I felt I had taken it as far as I could and I kind of plateaued. I was getting this voice to go in a different direction. As soon as I was finished, I did I, Keano. I had such a ball. It was an absolute confirmation that that's what I wanted to do."

She has never lived abroad for a substantial period of time – apart from a couple of months on her own in Italy doing a language course – and part of this move, although a professional one, is about expanding herself as a person, she says, learning, getting a new perspective. She wants "a complete break, a complete change", although she does admit, "It's an absolute gamble."

She has signed with one agent so far. She hasn't gone with a manager yet, and seems to be cautious about who she puts herself in the hands of. "One talked the talk, but didn't follow up as fast... It's kind of like the dating scene! If someone's not calling, they're not calling for a reason." He's just not that into you? "Yeah! Then there was another manager who was all over me, but I'm just not sure about it."

You should probably be very careful with all that kind of stuff, I venture. "Absolutely," she replies, solemnly. "I'm kind of trying to do it slowly, and the right way. I'm in things for the long haul. I want to act. But first of all, I have to find out if I'm good enough. I know right now there are loads of things I can do as an actress and can do very well, but there are lots of things that I don't feel confident about. There are things I have to delve into and see." She pauses. "It really is a voyage of self-discovery." Woah, deep.

Morahan checks herself. "Which sounds a bit wanky! Maybe you could put that in better words," she says, nodding towards the Dictaphone and cracking up.

She thought she was going to finish Off The Rails a season before she did. She thought the programme was coming to an end, and had made plans of her own. Then when another season came up, "that final season, I was definitely finished with the programme. I still enjoyed it, but I felt I wanted to leave enjoying it. I didn't want to go into autopilot. When things are getting to a stage where you feel things are getting repetitive..."

She stumbles a bit. "I think it was a really good time to leave. I knew I was finished. I knew the programme in that structure was over. I had already signed up to I, Keano at that point, but RTé hadn't decided what they were doing."

The station asked her not to discuss it. "It was a bit frustrating for me seeing headlines like 'Off The Rails Axed' and 'Caroline In Shock'. I was like, 'Oh for...'" She considers swearing but stops herself. "It was a really good lesson in rising above stuff, because I knew what was going on. I kept a dignified silence until they decided what they were going to do, but they took a long time deciding." Her and "Pam" still hang out. In fact, they met up last week for "a long lunch and a good natter".

TV work and profile building go hand in hand. If you're known, you get more work; if you get more work, you become better known, people want you at parties, PR heads want you at their events, and when your photo is everywhere then you're more recognisable for TV. It's an almost endless cycle – until you get tossed out. Morahan knows this part of the biz all too well from her days as the Evening Herald's social diarist. It must be tiring having to be 'on' all the time. "I'm more or less the same person on screen as off," she says. "When I'm walking around now, or getting here, walking around from Today FM in my battered jeans and North Face jacket, I'm not walking around 'on'. I don't feel the need. When I'm doing my shopping or out with my friends, I don't really notice people observing me, or the fact that they'll recognise me."

Will it be a relief not to have to live that life anymore – the launches, Social and Personal, VIP magazine kind of stuff? Does Caroline even go to launches anymore? "No. I don't have to go. When I was doing the social diary, I had to go to everything. A lot of them I'd find inanely boring. It was just work," she says.

"Now, I obviously don't have to do that. If I'm invited to film or theatre, I love it. But you do know that you have to stand there and get your picture taken no matter what. Quite often, I'd try to do a sneaky entrance into the film, but if the PR lady sees me, she'll literally grab me by the hand." She puts on a high-pitched PR voice. "'Hi! Caroline!' And you can't say no because that's just their job. The photographers, equally, if they see you and you're kind of skiving off, you're letting them down. Everyone is just trying to do their little job. God, I understand that more than anyone because I was the person going 'Could I talk to you for a sec?'"

Is she happy she doesn't have to go to the crappy launches anymore? "Oh yeah! I haven't had to for years." Morahan got the job in the Herald through pure neck, she admits. "I walked into the newsroom looking like I had just walked off a New York catwalk. They gave me the job and I was like," she adopts a couldn't-care-less voice, "'Yeah, sure no problem.' Then I walked out of the office and thought, 'S**t! I have to do that now', and it was traumatising! I would be painfully shy in those situations. I'd be walking up to someone in a room with my toes curled under my shoes trying not to sound like an absolute tool."

Is she as scared now? "Yeah! It's absolutely terrifying. But with all the career things I've done, I try to put The Fear in a top cupboard and close the door and deal with it when it comes along. I put it away, because if you think about all the worries and hang-ups that surround something, you'd never do anything."

While some of this comes across initially as self-help speak, Morahan clearly means what she says. She has forged a career based on clear stepping stones and ambition. Perhaps she's never been clear about where the next stepping stone is, but the path has been consistent. The fact that after several steps she's making a leap, doesn't, really, seem so surprising, given her progression so far.

And now, to the bright lights. She doesn't seem overawed by it until she mentions missing her family. Then there's a nervous sigh and she almost visibly tries not to talk about it. "I'm not pinning all my hopes on my name in lights, I just want to expand myself as a person. I was looking for something. I was hungry. I'm not kind of progressing. I really had, TV-wise, worked really hard, and I wasn't feeling challenged. So I just wanted to do something that would exercise different muscles. It's always been there in the background and it just got a bit too loud to ignore."

What can you say? Go for it.