The Waitomo Trail Run already has 1700 runners and walkers registered to explore the unique landscape.

It's now attracting celebrity attention.

Waitomo's Hole in the Rock. Photo: Kurt Matthews Photography.

Last year's Bachelor Art Green and Matilda Rice have signed up for the 33km course on Saturday.

Organisers describe the Trail Run as the most unique geographical trail on the planet, which takes runners and walkers underground and over-ground across stunning 6km, 11km, 22km or 33km courses.

The 22km and 33km course will take participants over towering rock faces, allow them to navigate through bush and over karst-studded landscapes, before descending the beautiful ‘Love Track'.

Following on from the Tarawera Ultra and Tarawera Trail Marathon, this is only the third event organisers Paul Charteris and Tim Day have offered in nine years.

Located in the ultimate playground in the Waitomo region, the course will weave runners and walkers through an underground and over ground thoroughfare of karst-studded landscapes, native bush, vibrant working farms, tunnels, canyons and glowworms.

The event is open to all ages and abilities.

The longest of the four events starts at Mangapohue Natural Bridge following one of the most unique geological lines in the world to finish at the world-famous Waitomo Glowworm Caves Visitor Centre

Participants of the 22 and 33km options are challenged to tackle the ‘adventure options' available on the course.

Tickets are still available for the 22km and 33km run/walk. Entry for the shorter distances is closed.

For more information, visit www.waitomo.com and www.waitomotrailrun.co.nz.