Zoo authorities in the Indian capital Delhi are holding a party to celebrate the 57th birthday of Rita the chimpanzee, its oldest resident.
The "birthday girl" will get presents and a cake will be cut in her honour, Zoo director Renu Singh told the BBC.
India's oldest living chimpanzee was born in Amsterdam in 1960 and arrived at Delhi zoo as a four-year-old.
She's a "very friendly" ape, Singh said. "We will cut a cake and I'll feed a big slice to Rita with my hands."
Schoolchildren will join today's celebrations - the party is being held a day early because Rita's birthday falls on a day when the zoo is closed.
Her presents will include a soft football and other toys, as well as a new blanket.