Derek William Bentley (30 June 1933 – 28 January 1953) was an English man who was hanged for the murder of a policeman, which was committed in the course of a burglary attempt.
 The murder was said at the time to have been committed by a friend and accomplice of Bentley's, Christopher Craig, then aged 16, but whether he had fired the fatal shot was later called into question.
 Bentley was convicted as a party to murder, by the English law principle of common purpose, "joint enterprise".
 The jury at the trial found Bentley guilty based on the prosecution's interpretation of the ambiguous phrase "Let him have it" (Bentley's alleged instruction to Craig), after the judge, Lord Chief Justice Goddard, had described Bentley as "mentally aiding the murder of Police Constable Sidney Miles".
 Goddard then sentenced Bentley to death: at the time, no other sentence was possible.
The black jack, "Caranx lugubris" (also known as the black trevally, black kingfish, coal fish and black ulua), is a species of large ocean fish in the jack family Carangidae.
 The species has a circumtropical distribution, found in oceanic, offshore waters of the tropical zones of the Pacific, Atlantic and Indian Oceans.
 The species is particularly prevalent around offshore islands such as the Caribbean islands in the Atlantic, Hawaii and French Polynesia in the Pacific and the Seychelles and Maldives in the Indian Ocean.
 Black jack are rare in shallow waters, preferring deep reefs, ledges and seamounts in clear waters.
 The species is easily distinguished by its black to grey fins and jet black scutes, with the head having a steep profile near the snout.
 The largest recorded length is 1 m and weight of 17.9 kg.
 The black jack lives either individually or in small schools, and is known to school with other species.
 It is a predatory fish, taking a variety of fish, crustaceans and molluscs as prey.
 Sexual maturity is reached at 34.6 cm in females and 38.2 cm in males, with spawning taking place between February and September in the Caribbean.
 The early life history of the species is very poorly understood.
 Black jack are of high importance to many island fisheries, but are rarely encountered in most continental fisheries.
 The species has a reputation as a gamefish, and is variably considered a terrible or excellent food fish, although several cases of ciguatera poisoning have been attributed to the species.
 The species was initially named "Caranx ascensionis" by Georges Cuvier, however several issues with the use of this name have seen Felipe Poey's name "Caranx lugubris" become the valid scientific name.
Derek William Douglas Bond, MC (26 January 1920 – 15 October 2006) was a British actor.
Mary Dick (1 June 1791- 14 July 1883) was the sister of William Dick, founder of the Veterinary College in Edinburgh.
Derek Martin (born Derek William Rapp on 11 April 1933) is a British actor who is best known for his role as Charlie Slater in the British soap opera "EastEnders" which he played from 2000–11, and briefly again in 2013 and 2016.
The Dick baronetcy in Prestonfield, Edinburgh was created in the Baronetage of Nova Scotia for James Dick.
 Initially created in 1677, it was renewed in 1707 and merged with the Cunningham of Lambrughton, Ayrshire baronetcy in 1829.
 The family seat was Prestonfield House, Edinburgh.
 Sir William Dick, 2nd Baronet and Sir Alexander Dick, 3rd Baronet were the younger sons of Sir William Cunningham, 2nd Baronet (of Lambrughton) and his wife Janet Dick, the daughter and heiress of Sir James Dick, 1st Baronet.
 Both brothers changed their surname to Dick on inheriting Prestonfield in turn.
Thomas Jacob "Jack" Black (born August 28, 1969) is an American actor, comedian, writer, producer, and singer.
 His acting career has been extensive, starring primarily in comedy films.
 He is best known for his roles in "Shallow Hal" (2001), "School of Rock" (2003), "King Kong" (2005), "The Holiday" (2006), the "Kung Fu Panda" franchise (2008–2016), "Tropic Thunder" (2008), and "Bernie" (2011).
 He has been nominated for two Golden Globe Awards.
 Black is the lead vocalist of the comedic rock group Tenacious D which he formed in 1994 with friend Kyle Gass.
 They have released the albums "Tenacious D", "The Pick of Destiny" and "Rize of the Fenix".
Derek William Dick (born 25 April 1958), better known by his stage name Fish, is a Scottish singer-songwriter and occasional actor.
 He achieved prominence as the lead singer and lyricist of the neo-progressive rock band Marillion from 1981 until 1988.
 In his solo career, Fish has explored contemporary pop and traditional folk.
The crevalle jack, "Caranx hippos" (also known as the common jack, black-tailed trevally, couvalli jack, black cavalli, jack crevale and yellow cavalli) is a common species of large marine fish classified within the jack family, Carangidae.
 The crevalle jack is distributed across the tropical and temperate waters of the Atlantic Ocean, ranging from Nova Scotia, Canada to Uruguay in the west Atlantic and Portugal to Angola in the east Atlantic, including the Mediterranean Sea.
 It is distinguishable from similar species by its deep body, fin colouration and a host of more detailed anatomical features, including fin ray and lateral line scale counts.
 It is one of the largest fish in the genus "Caranx", growing to a maximum known length of 124 cm and a weight of 32 kg, although is rare at lengths greater than 60 cm.
 The crevalle jack inhabits both inshore and offshore waters to depths of around 350 m, predominantly over reefs, bays, lagoons and occasionally estuaries.
 Young fish dispersed north by currents in the eastern Atlantic are known to migrate back to more tropical waters before the onset of winter; however, if the fish fail to migrate, mass mortalities occur as the temperature falls below the species' tolerance limits.
William Dick (1793 – 1866) was a Scottish veterinarian and founder of the Dick Vet School in Edinburgh, the first veterinary college in Scotland.
 He is responsible for major advances in the field of veterinary science and the profession as a whole.

Question: Besides actor , what profession do Jack Black and Fish (Derek William Dick ) have in common?
Answer: singer