Sunderland have undergone a transformation like no other during recent seasons.

Just five years ago the Black Cats were a regular feature in the Premier League and looked like contenders to really kick on, but unfortunately those times were coming to an end.

Back-to-back relegations saw the club into League One, with the Wearsiders still on a three-year journey to start moving their way back up the football pyramid.

Big-name signings are now a thing of the past for Sunderland, but the impact of such arrivals are still being felt by the club.

But who are the club's most expensive signings, and where are they now? We take a look.

The signing of the striker was seen as a real signal of intent for Sunderland.

After successful spells with Chelsea and Ranger Flo was brought to the Stadium Of Light in 2002 for a reported fee of £6.75million.

While making 33 appearances for the club the Norwegian frontman scored just six goals which wasn't enough to save the club from relegation that year, meaning that he moved on after just one season with the club.

Flo went on to play in Italy, England and Norway after leaving Sunderland but retired from the game in 2009 after leaving MK Dons.

Since then the striker has tried his hand at coaching and even a youth academy to help the next generation of players to thrive in the game.

The defender completed an £8million move to Sunderland after spending his entire career to date with West Ham United.

That move came in 2008 when he linked up with Roy Keane at the Stadium Of Light.

Despite spending three years with the Black Cats Ferdinand's time with the club was mixed at best as he struggled to nail down a spot in the first team squad.

In 2011 the centre-back moved on to join Queens Park Rangers, before spells in Turkey, England and Scotland saw him retire in 2019.

Since then Ferdinand has become a youth coach and an ambassador looking to increase inclusion in the game.

The goalkeeper moved to Sunderland in 2007 for a fee of £9million - a British record for a goalkeeper at the time.

Gordon spent five years in total at the Stadium Of Light but had his time at the club blighted by injury as a knee problem and a broken arm subjected him to lengthy spells on the sidelines.

That also saw plenty of competition for places at the club which made it hard for the Scottish goalkeeper to thrive.

In 2012 he went on to join Celtic where he spent six years before heading to boyhood club Heart Of Midlothian in 2020.

Gordon is still playing at Tynecastle and hoping to make a big impact as the club strives to reach the Scottish Premiership once again.

After successful spells with Ipswich Town, Charlton Athletic and Tottenham Hotspur the striker completed a £10million move to Sunderland in 2009.

Bent got his time at the club off to a perfect start with a goal on his debut and went onto enjoy a successful 18 months at the club before completing a controversial move to Aston Villa.

He then spent four years at Villa Park before moving to Derby County in 2015 where he saw out the last three years of his playing career.

Bent was regarded as one of the best goalscorers of recent years but retired in 2018 to take up a career in the media where he is regularly found on Sky Sports and TalkSPORT.

The player grew up in Sunderland before joining Middlesbrough's youth academy at the age of 12.

After making his debut at the age of 17 in a UEFA Cup clash with Sporting CP Johnson enjoyed an excellent few years with the Teessiders.

Johnson was understudy to Stewart Downing for much of his time at the club but became the main man when Downing moved on, a spell that showed exactly what the left winger had to offer.

Manchester City soon came knocking for the player, before he went to Sunderland for £10million in 2012.

He spent four years with the club before being sacked by the club after being charged with child grooming and sexual activity with a minor.

Jack Rodwell's £10million move to Sunderland may not be regarded as one of the club's greatest signings.

After proving himself as one of England's next top stars after coming through the ranks Everton, the midfielder spent five years as a first team player with the Toffees before moving to Manchester City in 2012.

Two disappointing seasons with City saw him complete a move to Wearside in what was seen as a huge signing for the club.

However Rodwell's time at the club wasn't without controversy with Sunderland suffering two successive relegations and the player reportedly refusing to take a pay cut.

He eventually left the club under a dark cloud in 2018 and spent time with Blackburn Rovers and Sheffield United in recent years.

After coming through the youth ranks with Reading the striker burst onto the professional scene with Ipswich Town.

Wickham made his debut in 2009 and spent two years with the Tractorboys as he built the reputation as one of the EFL's biggest talents - a reputation that secured him a move a £12million move to Sunderland.

He then spent four years with the Black Cats which included loan spells with Sheffield Wednesday and Leeds United during a mixed spell at the Stadium Of Light.

Wickham then completed a move to Crystal Palace in 2015 where he has been ever since.

However with his contract due to expire this summer it'll be interesting to see what the next move for the 27-year-old will be.

After bursting onto the scene with Hibernian, the striker established himself in the English game with successful spells with Burnley and Wolverhampton Wanderers.

That led to a permanent move to Sunderland in 2012 where he joined the club for a reported £12million.

Fletcher spent four years with the club, which included a loan spell with Marseille, before moving on to join Sheffield Wednesday in 2016.

He spent four years there before linking up with Stoke City in 2020 - a club where he is currently plying his trade in the Championship.

Fletcher will now be hoping that his experience can help the Potters to challenge for promotion to the Premier League next term.

Sunderland's second-most expensive signing ever.

Asamoah Gyan joined the Black Cats for a fee of £13million in 2010 and went on to enjoy an excellent first season with the club.

However his time at the club would be short-lived as a loan move to the United Arab Emirates followed the following year, before leaving the club on a permanent basis the next summer.

Since then the Ghana international has spent time in China, Turkey and India before returning to his native Ghana last summer.

Alongside football he's also turned his attention towards becoming a Boxing promoter and starting a start-up aviation business.

Sunderland's most expensive signing at a reported cost of £13.8million.

N'Dong joined the club in 2016 with the hope that he'd be able to take the club to the next level, however his first season with the club ultimately ended in relegation to the Championship.

After spending 18 months with the club the midfielder joined up with Watford on loan in January 2018, before being sacked by Sunderland the next summer for breach of contract.

Since then he's been playing in France with Guingamp and then Dijon, where he's currently plying his trade.

Unfortunately for Sunderland supporters the player certainly failed to live up to the initial hype that came with his big-money arrival.