The Duchess of Cambridge will join Sir David Attenborough at the Natural History Museum for the unveiling of its latest attraction - a vast blue whale skeleton.
Kate, who is a patron of the museum, and the famous naturalist will be among the first to see the 25-metre long skeleton suspended from the ceiling in the revamped Hintze Hall.
The whale skeleton has replaced Dippy the Diplodocus, which first went on display there in 1979.
When the museum announced it was dismantling the dinosaur display, 14,000 people signed a petition to stop the move.
But the museum went ahead, and soon the famous fossil will be going on a nationwide tour of museums and galleries, including a stint at Norwich Cathedral in 2020.
The Duchess will also tour Hintze Hall's 10 other new displays chosen from the museum's collection of more than 80 million specimens.
These displays aim to cover the history of Earth, and include a 4.5 billion-year-old meteorite, as well as the full skeleton of a mastodon, a distant relative of the mammoth.
Hintze Hall will reopen to the public on Friday following six months of refurbishment, and its displays will include a dinosaur fossil - an 120 million-year-old Mantellisaurus, found on the Isle of Wight in 1917.
Dippy's replacement, the blue whale, is the largest known animal on Earth.
After coming close to extinction, the animal became protected under international law in 1966, after which the blue whale population slowly began to increase.