The Bobby Moore Fund for Cancer Research UK is encouraging men, women and children to dig out their football shirts and wear them proudly on Friday 28 April to help fund life-saving research into bowel cancer.
The famous claret and blue has been worn by West Ham United for over a century and we've got the kits to prove it! To commemorate The Bobby Moore Fund with Cancer Research UK on #FootballShirtFriday, here are five of the best West Ham United kits of all time.
Worn for two seasons, the Hammers' third-placed finish in the First Division in 1986 was their highest league standing in the club's history.
A series of unfortunate injuries in the 1986-87 campaign meant the Hammers struggled to replicate their previous season's form, but this still remains an iconic home shirt.
In the white horizontal pinstripes, Frank McAvennie and Tony Cottee (right) scored a combined 71 goals in this number.
Having broken their major trophy duck during the 1960s, West Ham United continued their success in the next decade by claiming the 1975 FA Cup.
Despite debuts in the '60s, the 1970s saw the real emergence of new Hammers stars with the likes of Billy Bonds, Trevor Brooking, Frank Lampard and Clyde Best (left) all coming of age.
Away from home, this classic sky blue number, with two claret hoops oozed class and it sure transferred on to the pitch!
It's hard to argue that these West Ham legends didn't look the part, especially on the road.
The final season at the Boleyn Ground was memorable for many reasons: the Hammers second-highest Premier League finish, beating Manchester United on that famous farewell night and several top class performances in this top class shirt.
The shirt was a throwback to West Ham's first claret kit from the early 20th century, with its simplistic design and sky blue sleeves with the rounded collar. Text reading 'The Boleyn Ground: 1904-2016' was added below the crest and it all made for a shirt that would make every player and supporter proud to wear it.
Mark Noble and co. produced a fitting end to the 102 year stay at the Boleyn Ground and looked the part in doing it.
Celebrating a century of West Ham United, the Hammers wore this commemorative number when away from home between 1995 and 1997.
Whilst the 1990s failed to bring any significant silverware success to East London, this shirt will still live long in the memory!
Worn by the likes of Julian Dicks, Tony Cottee (left) and current manager Slaven Bilic, this shirt had unique bubble detailing, inside those the number '100' marking the hundred years of the club's existence. The large collars and claret double hoop design gave it a real 'yesteryear' feel.
The 1980 switch to an Adidas-designed home shirt began with this and what a start it was.
Adidas' trademark three stripes lined the Hammers classic sky blue sleeves, while the club crest was also redesigned. The shirt was finished with thick claret piping on the sleeves and a smart v-neck.
The 1980s began in perfect fashion for West Ham as they claimed the first FA Cup trophy of the decade.
Although their famous Wembley day out was enjoyed in the all-white away strip, this home number is still a fond reminder of a memorable era for the club.
The legendary likes of Trevor Brooking, Billy Bonds (right) and Alan Devonshire all wore this shirt.
Of course, the Hammers have had more than five great shirts in their history so if your favourite didn't make this shortlist, let us know on Twitter and use the hashtag #FootballShirtFriday!