Astrange thing happened the last time British-American rock band Foreigner played on an Irish stage. It was three years ago at the O2, and Californian singer Kelly Hansen was in the middle of dedicating a song to his late mother when, all of a sudden, the waterworks hit. We'd never before seen a rock star blubbering behind his microphone, but as it turns out, an emotional Kelly had his reasons.

"My mother was born and raised in Dublin," says the shaggy-haired 52-year-old. "She lived in Cabra West. When I was about 13, I came over for the first time, and that was interesting for me. It was the first time my mother had been over there since her mother had died. She was one of nine children, and there's only a few left now. Hopefully, they're all gonna be at the show, so we're gonna probably visit and have a ruby and a pint of Guinness."

Kelly might also leave room for a more traditional Irish meal while he's at it. "There's not a lot of knowledge about the history of my father's side, except that the name is Danish," he continues, "so I think that I gravitate towards the Irish background. And, of course, I love the Irish stew my mother used to make ... "

Good to know. 2014 marks Kelly's tenth year with Foreigner – a band that British axe-man Mick Jones (not to be confused with yer man from the Clash) originally formed in 1976 alongside US vocalist Lou Gramm. Foreigner has, of course, been through more line-up changes than Guns N' Roses and Jones (69) is the only member that has been involved since the start. Songwriter, producer and guitarist extraordinaire, he's also the man responsible for one of the most famous power ballads of all time (I Want to Know What Love Is – Foreigner's biggest hit).

There is little doubt that Foreigner is Jones's band despite not being its frontman in traditional terms. When Kelly, a singer best known for fronting a moderately successful 80s metal band called Hurricane, was asked to replace Gramm after he left for the second time, things changed. For everyone involved.

"I really wasn't happy with where my career was going," recalls Kelly. "I was doing a bunch of things in music, but I wasn't doing as much singing, and one day I just said to myself, 'Jeez, I'm really not doing the thing that I do best', and I decided to start redirecting my career." The first thing that he got involved in was auditioning for Jones, who had sent him a disc of instrumental Foreigner tracks to work with.

"I realised that they were talking about actually revamping Foreigner," says Kelly, "and that was very interesting to me. The band had come into town to rehearse and I jammed with them for about an hour and a half, and I remember distinctly that I got home about 6pm – I was in my kitchen, and management called me one hour later, at 7pm, and said, 'listen, we're booking shows for next weekend, can you start rehearsing tomorrow?' And that's how it happened."

Technically, Kelly is now Foreigner's fourth lead singer, and is the second-longest running vocalist in the job. "Yeah, I'm new-ish now, I guess," he says, laughing. "I think some people are still discovering that I'm in the band, and that's fine. For some people, you're always gonna be the new guy."

He always respected Foreigner's output during their mid-80s peak, and he never cared for the endless flak bestowed upon the band's cheesy, soft-rock anthems (Cold as Ice) and crazy guitar wig-outs (Juke Box Hero). Put it this way: Foreigner recently released a re-packaged collection of ballads in time for Valentine's Day – they know what their audience want, and the stats speak for themselves (75 million album sales and counting). What's more, it seems most fans have warmed to Hansen's presence. He finally feels like he's owns his spot in the band, too.

"I knew what I was coming into," he says of jumping on board back in 2005. "I knew that there were gonna be people that were gonna accept me, and there were people that weren't, but that wasn't my concern. My concern was trying to sing these songs and give them the credit that they're due."

There's never been any issue about standing out in front, either. "Well, Mick was really good about that. He gave me full support from the beginning. And I've been a lead singer my entire professional career, so I know what that spot is. I didn't hold back or play timid when we got out there."

In 2009, Foreigner released their first new studio album in 15 years, Can't Slow Down, coinciding with a renewed interest in the big-hearted, big-haired soft rock that encompassed much of what passed for American guitar music in the 80s (they even went on tour with Journey a few years back). However, things almost came to a halt in 2011 when Jones had to have emergency surgery after suffering a heart attack.

"Mick is getting better all the time," says Kelly. "He does have to watch it, and he does have to get advice from his doctors on when he can and can't do shows, but he's so much better than he was back in 2011, so we're happy to have him with us when he's playing with us."

As for Kelly, well, he remembers to look after himself too. "Being a singer, I was never a big partier, because I was always worried that I was going to hurt my voice, so in a way, that kind of helps keep you young as well – having a reason not to just completely obliterate yourself."

Last year, Billy Joel inducted Jones and Gramm into the Songwriters Hall of Fame. The duo even put aside their differences to perform together at the ceremony in New York. Naturally, rumours began to circulate online about a full-on reunion and a 'farewell tour' featuring Gramm on lead vocals. Kelly came across some stories himself. "I'm very involved in the day-to-day workings of what's going on with Foreigner," he says when I bring it up, "so I knew what the truth was, and it didn't really concern me. I don't have any ill will towards anybody ... but from a reality standpoint, I know that that's not gonna happen."

As for the future, Foreigner continue to work on new material ... and that's about all we know. For now. "I once had a girl tell me that she would happily stay with me if I promised her that we'd still be together in five years," finishes Kelly, "and I told her 'I might hate your guts in five years, why in the world would you ask me to make that promise?' And the way I look at this is as long as people enjoy coming to see this band and hear these tunes and as long as I'm able to do it at a level that is acceptable to me, then that's what I'd like to do ... "

Foreigner play the Olympia Theatre, Dublin on Monday and the Waterfront Hall, Belfast on Tuesday.

A change out front

Depending on who you ask, Foreigner have somehow avoided turning into their own tribute act. “In this band, members started to change after the second record,” says Kelly, “so this has not been a band that if you’re a fan, you expected it to always be the same people.” Apparently, it’s all about carrying on the legacy with integrity. But switching singers can be a tricky business for some...

Queen

They’ve never broken up, and guitarist Brian May and drummer Roger Taylor continue to trade under the name Queen, be it with Paul Rodgers out in front or, more recently, US singer Adam Lambert. Neither could ever be a match for the late, great Freddie Mercury, though.

Journey

In 2007, American rock band Journey’s, er, journey to find a suitable replacement for Steve Perry ended when they came across a Filipino singer named Arnel Pineda covering their songs on YouTube. Arnel landed himself a dream job, and a year later, Journey’s new album, Revelation, became their highest-charting release in almost a decade.

Thin Lizzy

There was no need to revive Thin Lizzy. Alas, in 1996, ten years after Phil Lynott’s death, members of the band reconvened to hit the road under the Thin Lizzy name with John Sykes on lead vocals. It was never the same. In 2012, its members — including Scott Gorham and new frontman Ricky Warwick — started calling themselves Black Star Riders in order to release new material.

AC/DC

Following the untimely death of lead singer Bon Scott in 1980, Australian rock band AC/DC considered calling it quits. In the end, they decided to bring in a new vocalist, hiring Brian Johnson and recording Back in Black. The rest, as they say, is rock ’n’ roll history.

Day & Night