Question: Which of the following is known for his role in the drama "Mystic River": Larry Hagman or Sean Penn?

Context articles: Three's a Crowd (1969 film)
J. R. Ewing
Mystic, Connecticut
Larry Hagman
Mystic River (film)
Mystic River (Connecticut)
Mystic River Reservation
Mystic River Bascule Bridge
Sean Penn
Mystic River Historic District

Three's a Crowd was a made-for-TV movie that was originally aired by the ABC network on December 2, 1969.
 The film was a comedy directed by Harry Falk and starred Larry Hagman, who was starring in the hit TV sit-com "I Dream of Jeannie".
 Hagman plays a pilot whose wife, portrayed by E. J. Peaker, disappears and is presumed dead.
 Seven years later, she appears.
 Meantime, Hagman has met and married Jessica Walter.
John Ross "J. R." Ewing Jr. is a fictional character in the U.S. television series "Dallas" (1978–91) and its spin-offs, including the revived "Dallas" series (2012–14).
 The character was portrayed by Larry Hagman from the series premiere in 1978 until his death in late 2012, and Hagman was the only actor who appeared in all 357 episodes of the original series.
 As the show's most famous character, J. R. has been central to many of the series' biggest storylines.
 He is depicted as a covetous, egocentric, manipulative and amoral oil baron with psychopathic tendencies, who is constantly plotting subterfuges to plunder his foes' wealth.
Mystic is a village and census-designated place (CDP) in New London County, Connecticut, United States.
 The population was 4,205 at the 2010 census.
 Mystic has no independent government because it is not a municipality in the state of Connecticut; it is located within the towns of Groton (west of the Mystic River, and also known as "West Mystic") and Stonington (east of the Mystic River).
Larry Martin Hagman (September 21, 1931 November 23, 2012) was an American film and television actor, director and producer best known for playing ruthless oil baron J.R. Ewing in the 1980s primetime television soap opera "Dallas" and befuddled astronaut Major Anthony "Tony" Nelson in the 1960s sitcom, "I Dream of Jeannie".
Mystic River is a 2003 American mystery crime drama film directed and scored by Clint Eastwood.
 It stars Sean Penn, Tim Robbins, Kevin Bacon, Laurence Fishburne, Marcia Gay Harden, and Laura Linney.
 The screenplay by Brian Helgeland was based on the novel "Mystic River" by Dennis Lehane.
 The film was produced by Robert Lorenz, Judie G. Hoyt and Eastwood.
 It is the first film on which Eastwood was credited as composer of the score.
The Mystic River is a 3.4 mi estuary in the southeast corner of the U.S. state of Connecticut.
 Its main tributary is Whitford Brook.
 It empties into Fishers Island Sound, dividing the village of Mystic between the towns of Groton and Stonington.
 Much of the river is tidal.
 The Mystic River was the location of three large shipbuilding firms during the 19th-century, and it is now the home of the Mystic Seaport maritime museum.
 The name Mystic, as the modern spelling has it, is derived from the Pequot term "missi-tuk", describing a large river whose waters are driven into waves by tides or wind, according to the Mystic River Historical Society.
The Mystic River Reservation is a publicly owned nature preserve with recreational features located along the Mystic River in the towns of Winchester, Arlington, Medford, Somerville, Everett, and Chelsea in eastern Massachusetts.
 The reserve is part of the nearly 76 sqmi Mystic River watershed.
 It is managed by the Massachusetts Department of Conservation and Recreation.
The Mystic River Bascule Bridge is a bascule bridge spanning the Mystic River in Mystic, Connecticut in the United States.
 It carries vehicle and foot traffic directly into the tourist district of town via 33 ft Main Street (U.S. Route 1).
Sean Justin Penn (born August 17, 1960) is an American actor, filmmaker, and political activist.
 He has won two Academy Awards, for his roles in the mystery drama "Mystic River" (2003) and the biopic "Milk" (2008).
The Mystic River Historic District encompasses the part of the village of Mystic, Connecticut that is on the Groton side of the Mystic River.
 The district was added to the National Register of Historic Places on August 24, 1979, approximately 235 acres that includes much of the village now known as West Mystic and many buildings from the 19th century.