A giant sculpture of a spider, similar to one which has been luring the crowds to Tate Modern on London's South Bank, has been donated to the gallery.
Bourgeois made a series of spider sculptures in the 1990s
Louise Bourgeois' 9-metre-high work, titled Maman, was part of Bourgeois' inaugral commission for The Unilever Series in the Turbine Hall in 2000.
A smaller version is currently on display outside the gallery as part of the Bourgeois retrospective.
Tate Modern director Vicente Todoli said it was an "historic moment".
The steel and bronze sculpture has been given to the Tate by its creator and an anonymous benefactor.
It is the largest spider work made by French-born artist Bourgeois, now 96, who also cast six bronzes from the original.
Mr Todoli said: "To acquire Maman, one of Louise Bourgeois' best-known and seminal works, the largest of her spider sculptures, is an historic moment for Tate.
"This work significantly enhances our holdings of the work of one of the world's greatest living sculptors."
Bourgeois, who lives in New York has described the piece as "an ode to my mother, my best friend".
She added: "Like spiders, my mother was very clever. Spiders are friendly presences that eat mosquitoes.
"We know that mosquitoes spread diseases and are therefore unwanted. So, spiders are helpful and protective, just like my mother."
The retrospective, simply titled Louise Bourgeois, runs until 20 January.