A lot has changed in the 13 years since Vanessa Carlton last visited Scotland.

Back then, she was the piano-playing pop star best known for her hit A Thousand Miles.

That’s still her most famous song, but as the years have gone by she’s left the major labels and found her own musical identity.

Oh, and she got married, with Stevie Nicks of Fleetwood Mac officiating at it.

“When you get discovered as a 19-year-old artist, you need to be overly defensive about what you are, and it’s hard going,” says the songstress, ahead of a Glasgow gig at SWG3 tomorrow night.

“Throughout my experiences on labels there were a lot of older male executives telling me what to wear, or how I should look, and it’s laughable, but it can really bum you out, too.

“When I hit 29, that’s when I really started getting my act together and I’d recovered from that pop success. Yes, I was successful, but it was a difficult time too, and I managed to regroup and figure out my priorities.”

The key turning point was her 2011 albums Rabbits On The Run. Although still a poppy record, it’s also much dreamier than her previous songs, while adding in ideas like a children’s choir. The 35-year-old has now taken another step forward with Liberman, her fifth album and another classy collection of thoughtful pop music.

She’s aided on the record by producer Steve Osbourne, who Vanessa sought out after hearing his work with Doves on their Last Broadcast and Lost Souls albums.

“I call myself a late bloomer, because it wasn’t until I’d left the major labels that I felt I had the confidence to try new ideas for an album without any distractions,” she says.

“Rabbits On The Run was a huge, huge turning point as an artist and as a person, so Liberman is a natural progression from that fundamental shift that happened back in 2010. It’s not like there’s a live band in the studio playing these songs, it’s two people playing and singing different parts, and then trying to turn them into different colours.”

Vanessa met Steve thanks to her pal KT Tunstall, who introduced the two of them at a party a few years ago. The Scottish songbird has been friends with Vanessa for years, going back to them spending time on a boat together…

“KT’s a friend of mine, and a cool lady,” adds Vanessa.

“KT and I met on a ship, actually – there was a group called Cape Farewell, who had this boat, this expedition, with singers and artists on it. So we went on a cruise up through Greenland to look at climate change, and we had the exact same luggage. We ended up talking and becoming friends from there, and then she introduced me to Steve a few years ago, at a bonfire party she was having.”

While Vanessa hasn’t abandoned her past songs (fans of A Thousand Miles will be pleased that it’s still a regular in her sets) the singer feels that she is now making music that reflects her better now.

“I had come out as this pop star with very produced records, and while I was certainly a part of that, at the same time I don’t think it was an authentic reflection of who I was at the time or who I am now.

“It’s been an interesting arc, and I’ve ended up happier because I feel more myself.”

She also found happiness offstage, marrying John McCauley of the band Deer Tick in 2013, and giving birth to a daughter in January last year (when she answers the phone she’s sitting with her child on their porch).

Her marriage also featured Stevie Nicks officiating at it, which isn’t exactly common…

“We’ve been going strong ever since, so I think Stevie might be a good luck charm,” adds Vanessa.

“Stevie and I have been friends since about 2004, when she asked me to open for her on her solo tour, and over the years we got really close. She was there in the hospital when I had my daughter, and she’s one of those artists where she’s a great mentor to younger women and also a great friend.

“She’s a fantastic example of a woman who’s been through a lot of ups and downs, and come out stronger. I really admire her, so I couldn’t think of anyone else better to be there for my nuptials.”

Vanessa Carlton, SWG3, tomorrow, £15, 7pm