Robert Downey Jr. might have laid Iron Man to rest, but he hasn't entirely abandoned the world of franchises.

The star of 'Dolittle' (one of the highest grossing movies of 2020 - depressing right?) has indicated his plans for future 'Sherlock Holmes' movies.

He and producing partner Susan Downey spoke about future movies and spin-offs at the Fast Company Innovation Festival.

"At this point, we really feel that there is not a mystery-verse built out anywhere, and Conan Doyle is the definitive voice in that arena, I think, to this day," Downey said.

"So to me, why do a third movie if you’re not going to be able to spin off into some real gems of diversity and other times and elements?"

The actor spoke about drawing inspiration from the success of the MCU.

"I do think that the decade of tutelage and observation, what we were both able to have with Marvel, watching them build out and see all the opportunities, was invaluable. It was like a master class," Susan Downey noted.

"And they really did know what they were doing and they had this tight-knit group of people from the jump locked into a vision that enables them to broaden."

They plan to expand to TV and on demand with the series, targeting such outlets as HBO and HBO Max. They've had success with the latter streaming service with 'Perry Mason'.

Robert Downey Jr. emphasised though that they won't be mimicking Marvel.

"We’re not repeaters," he said. "We don’t want to just do what’s been done somewhere else.

"But I think the model itself has become much more dimensionalised than it was before."

'Sherlock Holmes 3' sees the return of Downey in the titular role and Jude Law back as Watson.

Dexter Fletcher directs, and it's meant to hit cinemas December 2021. But with all the postponed release dates, this is likely to change.

Other recent successful adaptations of Arthur Conan Doyle's works include the BBC series 'Sherlock' and Netflix's recent 'Enola Holmes'.