Norwegian Cruise Line has signed up reality TV star Jillian Michaels to lead a wellness cruise this October, adding to the host of "wellbeing" options available at sea.

The cruise, which will depart October 21 from the US city of Miami, Florida, will focus on health and fitness with the assistance of Michaels, who starred in the hit TV series The Biggest Loser.

Billed as "four days of healthy cuisine, heart-pounding exercise, and live entertainment," the "Ultimate Wellness Cruise" will see the Norwegian Star sail to the Bahamas with prices from $649 (€533).

On-board, the health and fitness guru will lead group workouts (simulcast to all cabins), team sports and workouts for all the family.

Cuisine on board will also be selected by Michaels, who will be speaking several times during the cruise on how to eat healthier, exercise better and "improve all aspects of your life."

Onboard wellness is big business for cruise lines, which tend to play host to older, wealthier customers.

The Seabourn Sojourn, a new liner due to debut in London in June, will host an 11,400 square foot (1,059 square meter) spa, complete with a Kneipp Therapy Walk, a water course separated into areas of cold and warm water "stimulating capillary circulation and metabolism, and soothing pain."

"Wellness and fitness are so important to consumers today," explains Pamela C. Conover, Seabourn's President and CEO. "We are seeing more and more guests seeking to keep up their healthy lifestyle even when they are traveling."

Sojourn's spa will also feature a Spa Villa, a treatment area large enough for duet treatments, complete with shower; a bathtub big enough for two; a private balcony for sunbathing and a full living room area.

Nine-to-12-day voyages on the new Seabourn Sojourn in Northern Europe start from $4,999 cruise-only (around €4,100).