Former First Lady Nancy Reagan, wife of Ronald Reagan, has died at the age of 94 at her home in Bel Air after a period of ill health.

Reagan was first lady of the US between 1981-1989 when her husband, Ronald, was in the White House. She was a seminal figure in the former president's political life, fiercely defending his politics and accompanying him on his major diplomatic visits.

A spokesman confirmed the cause of death as heart failure. It is understood that Reagan had been in ill health since around 2008, when she broke her pelvis, and suffered a fall at home in 2012 when she broke three ribs.

A fine romance

Born in New York in 1921, Reagan was an actress during the 1940s and met Ronald in 1949 when he was president of the American actors' union the Screen Actor's Guild. She had been surprised to find her name, then Nancy Davis, on the Hollywood "black list" of Communist sympathisers. It later turned out that the listing was for another actress with the same name, and after Ronald solved the problem they began seeing each other.

"I don't know if it was exactly love at first sight, but it was pretty close," Nancy said, recalling their first date decades later.

They married in 1952 and a decade later she retired from acting, but not before appearing alongside her husband in at least one movie and a TV show.

Political figure

Nancy Reagan was first lady between 1981-1989, while Ronald Reagan served his two terms as US president. Even in the public eye, the couple were not afraid of showing affection, leading Charlton Heston to famously describe them as "the greatest love affair in the history of the American presidency".

Even hardened White House hacks admitted to being moved by the couple's relationship: "We would turn aside because we felt that there was something very special, private and wonderful going on between them," a former NBC White House correspondent said.

But it was reported that Nancy had a sometimes fractious relationship with her husband's senior staff and even contacted an astrologer following the attempted assassination attempt against the president in 1981. The couple would re-arrange meetings depending on horoscopes as Nancy sought increasingly to control access to her husband during the decade he was in the White House.

Nancy Reagan was also a political force in her own right, campaigning against the use of recreational drugs and launching the "Just Say No" campaign. She addressed the UN General Assembly in 1988 on the issue of the drugs trade, arguing that the US had to tackle the demand for cocaine at home as well as pressuring foreign governments.

A breast cancer survivor, she also lobbied for better education surrounding the disease.

In 2007, the intensely private Nancy Reagan gave a peek into her life with President Ronald Reagan in an interview with Larry King CNN

Nancy nursed her husband throughout the 10 years he suffered from Alzheimer's disease, until his death in 2004 aged 93.

She is survived by her two children, Patti and Ron.