The movie stars began dating in 2007 and wed in September 2008.
"After long and careful consideration on both our parts, we've decided to end our marriage," the actor and actress said in a joint statement issued Tuesday to People.com. "We entered our relationship with love and it's with love and kindness we leave it. While privacy isn't expected, it's certainly appreciated."
A source told People.com the couple broke up six months ago, with Johansson initiating the split.
Reynolds, 34, has starred in the blockbusters "The Proposal" and "X-Men Origins: Wolverine." Currently People magazine's Sexiest Man Alive titleholder, he will soon be seen playing the superhero the Green Lantern on the big screen.
Johansson, 26, is best known for her work in the films "Girl with a Pearl Earring" and "Lost in Translation." She won a Tony Award this year for her work in the Broadway revival of "A View from the Bridge."
JENNIFER CONNELLY: Jennifer Connelly's publicist has confirmed the 40-year-old American actress is pregnant with her third child.
TVGuide.com reported the happy news Tuesday.
This will be the second for Connelly and her husband, actor Paul Bettany, whom she married in 2003. They are also the parents of a 7-year-old son.
The actress has a 13-year-old son from a previous relationship.
Connelly and Bettany co-starred in "A Beautiful Mind," the film for which the actress earned her Oscar.
CHARLIE SHEEN: Charlie Sheen will not face charges for an alleged incident at a posh New York hotel last October, law enforcement sources told TMZ.
A reputed adult-film actress accused the actor of assault and battery, as well as false imprisonment, during a night she spent with him at Manhattan's Plaza Hotel.
Media reports said at the time the "Two and a Half Men" star was intoxicated and trashed his hotel room, then went to the hospital. However, Sheen's publicist has maintained the actor needed treatment because he had an adverse reaction to medication.
TMZ said Tuesday prosecutors in New York decided not to bring charges against Sheen because they do not believe he engaged in any criminal conduct.
MICHAEL C. HALL: U.S. television stars Michael C. Hall and Jennifer Carpenter have announced they are divorcing after nearly two years of marriage.
The "Dexter" co-stars wed Dec. 31, 2008. During the course of their brief marriage, Hall underwent treatment for Hodgkin's lymphoma.
"Having been separated for some time, Jennifer Carpenter and Michael C. Hall have filed for divorce," representatives for the couple said in a statement issued exclusively to Entertainment Weekly Tuesday.
The publicists categorized the split as amicable.