Jemma Gwynne Griffiths, known by her stage name Jem, is a Welsh singer, songwriter, and record producer. Born in Penarth, Glamorgan, on 18 May 1975, she developed a passion for music at an early age and began songwriting while attending Stanwell School. After graduating from the University of Sussex in 1996, she worked as a DJ and co-founded the record label Marine Parade in Brighton. Jem's music career took off when she released her debut studio album, "Finally Woken," in 2004. The album achieved platinum certification in the United Kingdom and produced hit singles such as "They," "Just a Ride," and "Wish I." Her success continued with the release of her second album, "Down to Earth," in 2008, followed by her third album, "Beachwood Canyon," in 2016.Jem's journey in the music industry has been marked by her collaborations with renowned producers and her music's inclusion in popular television programs and films. Her distinctive sound and meaningful lyrics have resonated with audiences around the world. Jem's dedication to her craft and her ability to evolve musically have solidified her status as a respected artist in the industry.

James "Jem" Mace (8 April 1831 – 30 November 1910) was a renowned English boxing champion who made a significant impact during the bare-knuckle era. Born in Beeston, Norfolk, he gained fame as one of the most scientific boxers of his time. Mace's remarkable career saw him clinching the English Welterweight, Heavyweight, and Middleweight Championships between 1860 and 1866. Notably, he held the World Heavyweight Championship from 1870 to 1871, solidifying his status as a dominant force in the boxing world. Before his boxing career, Mace worked as an apprentice sawyer and also showcased his musical talents as a violinist.Mace's journey to greatness included exhibition boxing at Nat Langham's Rum Pum-pas boxing club, where he once faced Archibald William Douglas, the 8th Marquess of Queensberry. Throughout his career, he demonstrated exceptional skill and precision in his matches, earning recognition for his speed and strength. His victory over Posh Price in a rough and damaging match at a young age showcased his characteristic scientific boxing style. His legacy as the English heavyweight champion in 1861 and his numerous victories against formidable opponents solidify his position as a boxing legend. James "Jem" Mace's contributions to the sport continue to inspire aspiring boxers and enthusiasts worldwide.

James "Jem" Mason (c. 1816 – 1866) was a renowned English jockey who achieved fame by winning the Grand National in Liverpool on the brown-bay racehorse, Lottery, on 26 February 1839. Hailing from Stilton, Cambridgeshire, he came from a family involved in horse dealing and began his professional riding career in 1834, securing his first victory at St Albans. Known for his impeccable fashion sense and association with the nobility, Mason continued competing until 1848, although he was unable to replicate his initial triumphs. Harriet Howard, who later became Napoleon III's mistress, lived with Mason from a young age. Despite marrying twice, his first marriage to Charlotte Mary Zoe Elmore, daughter of horse dealer John Elmore, ended in divorce. Mason's life was tragically cut short by throat cancer in 1866. His legacy as a talented and stylish jockey endures in equestrian history.

Jeremy George Weston "Jem" Marsh (15 April 1930 – 2 March 2015) was a prominent British engineer, motor manufacturer, and race driver, hailing from Clifton, Bristol, England. His foray into the motor industry began with Speedex Castings and Accessories Ltd., a company based in Luton that specialized in producing and selling tuning parts for Austin Sevens, inspired by Marsh's Speedex750 racing special. However, Marsh is most renowned for co-founding the sports car manufacturer Marcos, which garnered its name from a fusion of his and his co-founder Frank Costin's surnames. The company, established in 1959, was later managed by Jem's son, Chris Marsh, before being acquired by Tony Stellinga from Canada. Marcos continued to manufacture automobiles until 2008, when production ceased. Marsh's legacy in the automotive industry remains indelible, and his contributions have left an enduring mark on the world of motor engineering and racing.