She's graced theatre stages, film screens and podiums worldwide, but the rainforest proved to be a thrillingly novel environment for Judi Dench during filming for her new two-part documentary, Judi Dench's Wild Borneo Adventure.

"When you're in the middle of it, you can't express how remarkable it is," says the 84-year-old actress, whose fondness for forests was highlighted in last year's BBC One programme, My Passion For Trees.

As part of her latest wildlife project, starting on STV on July 2 at 9pm, the great Dame spent two weeks in the jungles of Borneo with her "chap", conservationist David Mills, meeting a plethora of exotic animals and finding out about conservation work being done to protect their habitats.

"I've been to a lot of places in the world, but I've never been to anywhere like that," she says of the world's third largest island, which is divided between Malaysia, Indonesia and Brunei. "It does take your breath away. It's wildly beyond your imagination."

These are some of her highlights from filming...

Climbing one of the world's tallest trees

On a light aircraft ride above the island, Dench discovers she is looking at some of the oldest rainforests in the world, which have been in existence for more than 100 million years. They are also home to some of the tallest trees on our planet, towering up to 100 metres high.

To get a closer look, Dench is strapped into a seated harness and hoisted to the top of one. "I wasn't remotely nervous at all," she insists, recalling the experience. When asked what it was like to be high up in the canopy, she smiles and replies matter-of-factly: "It's tall."

Catching a baby croc

One of the most nerve-wracking scenes takes place at night when Dench joins biologists on a mission to take DNA samples from crocodiles on the Kinabatangan river. Recounting the moment a baby reptile was hand-plucked from the water, Dench says: "It was calling for it's mother! Thank God I'm short-sighted." Despite her initial reservations, she did eventually connect with the croc. "While it was being tagged - I got to hold its foot, a soft palm. It was very, very nice."

Getting intimate with insects

Creating a riot of noise and colour, up to 80,000 insects can be found in Borneo - one tenth of the number existing on our planet. Dench is fascinated by the creepy crawlies; she's stunned by the beauty of a dung beetle called Bob, comes within centimetres of a deadly centipede and even has to fend off an amorous stick insect. "It was the biggest stick insect in the world," she says. "I said, 'Oh, that's charming' and it went and sat straight on top of my head."

Planting trees for a green future

Although deforestation is a major threat to the wildlife of Borneo, Dench is upbeat about work being done to strike a sustainable balance between the economic necessity of a palm oil industry and conserving natural habitats. She joins a group of multi-generational women who are replanting trees on a patch of land donated by a plantation, with the aim of creating a wildlife corridor.

Demonstrating their commitment to the cause, Dench and David Mills have been announced as patrons of the South East Asia Rainforest Research Partnership (SEARRP), a charity supporting scientific research concerning environmental issues in the tropics.

Holding hands with an orangutan

For some time, Dench has been touched by the plight of orangutans, and even before arriving in Borneo, she had adopted three of the great apes. So, meeting three-year-old orphan Bigiya was always destined to be a "never to be forgotten moment". Recounting the episode, she's choked with emotion. "He didn't take my hand immediately. It was like a child looking at me... waiting until he was absolutely sure."

Judi Dench's Wild Borneo Adventure starts on STV on July 2 at 9pm.

For more information on SEARRP and making donations, visit searrp.org/giving. For more information on The Rainforest Trust, visit rainforesttrust.org.