Benedict Cumberbatch, star of Marvel’s Doctor Strange movie and of course TV’s Sherlock, has a side hustle as an investor in start-ups.

Back in 2016, Benedict Cumberbatch invested in a second seed round for Tentrr, essentially an Airbnb for camping enthusiasts, bringing its total funding to $3.5m at the time, which it used to launch its first five campsites.

The app itself is simple: landowners with at least 10 acres of private property register to list their sites on Tentrr, and users looking for outdoorsy retreats browse listings and pay per night. The sites are completely hassle free (there’s no check-in or exchanging of keys) and camp sites are equipped with everything you might need.

Tentrr campsites are now available right across the US, which appealed to Cumberbatch, who is a keen walker himself. “I love hiking…It’s great to get away in nature. It’s grounding,” he said at the time.

The start-up investment must have given Benedict Cumberbatch a taste for angel investing. The following year he invested in New York-based texting app ScribbleChat as part of a $2.75m seed round.