"Tom Holland is in 'Dolittle' because of Robert," the film's director Stephen Gaghan said about the reason behind the duo's reunion.
"Tom did the movie because he loves Robert. They're very close."
In "Dolittle", Downey Jr. portrays the role of famed doctor and veterinarian of Queen Victoria's England who lives in solitude behind the high walls of Dolittle Manor, with only his menagerie of exotic animals for company.
Holland lent his voice to Jip, an intelligent and loyal long-haired lurcher dog who is sight-challenged.
"Dolittle" is about a veterinarian who could talk to animals and was forced to set on an adventure when the young queen (Jessie Buckley) falls ill. A reluctant Dolittle is forced to go on an epic adventure to a mythical island in search of a cure, regaining his wit and courage as he crosses old adversaries and discovers wondrous creatures.
The doctor is joined on his quest by a young, self-appointed apprentice (Harry Collett) and a coterie of animal friends, including a gorilla (Rami Malek), a duck (Octavia Spencer), a bickering duo of a cynical ostrich (Kumail Nanjiani) and a polar bear (John Cena) and a parrot (Emma Thompson), who serves as Dolit'le's most trusted advisor and confidante.
The film will be released in India by Universal Pictures on January 17 in English, Hindi, Tamil and Telugu.