Tales of the riverbank: At home with Jonathan Ansell

I live in Battersea, in the penthouse of one of the first riverside developments built in the late Eighties. There are balconies off the living room and master bedroom, where we sit out and enjoy fantastic views of the river. I can see Battersea Power Station and all the buildings in the City, like the Gherkin.

Before G4, I was living in Charlton, in a ground-floor flat in a bog-standard Victorian terrace with a bunch of students. We didn't have a living room because I was living in it! When G4 started, we lived all over London and it was a nightmare picking each other up and dropping each other off at the beginning and end of the day. So we looked at the whole map of London for a good place to live and work from and picked Battersea. We rented – and then bought – flats close to each other. We thought, "Let's make it easy and all live in one place and enjoy this mad roller coaster."

At first, I rented in a brand-new development in Battersea, where I had unrestricted views of the whole of London from Wembley Stadium across to Canary Wharf. I was paying £1,850 a month, a dramatic increase from Charlton, where three of us were paying £600 a month. It was silly spending so much in rent, so I took the step to buy and get on the property ladder.

Two and a half years ago, I bought a flat on the third floor of the block where I live now. Then, last June, I sold that place to buy the penthouse on the fourth and fifth floors with my girlfriend, Debbie. We met two years ago, when we were very drunk, in a nightclub on Tottenham Court Road. Meeting like that doesn't work for a lot of people, but it worked for us.

Our home is upside down. Upstairs is the dining room, kitchen, second bedroom and bathroom; downstairs is the master bedroom with an en-suite bathroom and the living room. The dining room is on a mezzanine and linked to the living room by a spiral staircase. I love the strip lights that I fitted to the staircase. You operate them with a remote control and can make them flash different colours. It turns people's heads when they come round for a party.

The whole flat is painted in neutrals – white and cream. The kitchen is annoyingly dated with blue, green and red tiles and beech units. I'd like to revamp it with granite and big gas burners, and I want to rip the wall out between the dining room and kitchen to make it open-plan.

My favourite room is the living room. It has a 16ft-high ceiling and there's a huge exposed brick fireplace that runs from floor to ceiling. I have a corner sofa with loads of cushions. It's from Ikea – I'm a sucker for Ikea. The sofa is something I've had for a long time and needs replacing. Debbie wants a suede one but I'm worried it will get dirty. We are arguing that one out at the moment!

Throughout my life, I've kept fish and over the years my aquariums have got bigger and bigger. Now, in our living room, I have a six-foot-long unit. I have parrot fish, which I have had since they were babies – now they are five inches long. They look like they are smiling the whole time and have lots of personality – they come up and say hello. There's a loach called Dougal. Some friends bought us a couple of albino tiger barbs, which we named Simon and Charlotte after them.

I have my discs on the wall behind the sofa, so I don't have to stare at them the whole time. They are little reminders of how I ended up getting this flat. We got a double-platinum disc for the first G4 album, platinum for the second and gold for the third. The maddest reminder is a framed album chart, which celebrates our No 1 position in the charts the week we released our first album. It's very strange when you look at the other people who released albums that week – Jennifer Lopez was No 8.

Being in G4 was fun and enjoyable, and having that life-change with college mates was the ultimate experience. When we split up in 2007, there wasn't an official falling out, but we did get annoyed and frustrated with each other. We all had different focuses in our heads and we all promised ourselves that if that happened, we would walk away. Now we are all busy doing different things. We've have had some space from each other and now we can get our friendships back. In fact, Mike, having moved away from Battersea, has just moved back and we are hoping to have a pint again soon.

Ansell stars as Nanki-Poo in 'The Mikado' (Richmond Theatre 9 to 13 Sept / Alexandra Theatre Birmingham 23 to 27 Sept). He begins a nationwide tour in 'A Night at the Opera' (30 Oct to 23 Nov) and in November releases a new album called 'Forever'

Jonathan Ansell, 26, was a student at the Guildhall School of Music & Drama when he and three fellow students were runners-up on 'The X Factor' in 2004. The quartet had huge success as the pop-opera group G4, but disbanded in 2007. Ansell then signed a record deal with Universal and released his debut album earlier this year. He lives in Battersea with his partner, the television presenter Debbie King.