The GTS Finnjet was a cruiseferry, built in 1977 by Wärtsilä Helsinki Shipyard, Finland for Finnlines traffic between Finland and Germany. At the time of her delivery, Finnjet was the fastest, longest and largest car ferry in the world, and the only one powered by gas turbines. At the point of her scrapping in 2008, she remained the fastest conventional ferry in the world, with a recorded top speed of 33.5 knots (62.0 km/h; 38.6 mph).

Finnjet had remained out of service since 2005, laid up in Baton Rouge, Freeport and Genoa. Although she was purchased by Club Cruise in November 2007 and renamed MS Da Vinci in January 2008 for rebuilding into a cruise ship, the ship was sold for scrap in May 2008. Following the sale she was renamed MS Kingdom for her final voyage to the scrapyard in Alang, India where scrapping finally started in September 2008.

Finnjet was built by Wärtsilä at the Helsinki Shipyard (Build-No. 407) in Helsinki, Finland and delivered to Enso-Gutzeit to serve in their subsidiary Finnlines. The ship was built specifically for the route between Helsinki in Finland and Travemünde in West Germany which Finnlines had previously trafficked with slower conventional ferries. The gas turbine engines combination gave a top speed of 31 knots (57 km/h), a one-way crossing was planned to take only 22 hours for the ship. At the time Travemünde was the closest port to Finland in mainland Western Europe, being located in the Federal German state of Schleswig-Holstein just west of the border with East Germany.

In addition to being the largest and fastest ship of her time, Finnjet is also widely considered to have been the first genuine cruiseferry. Her cabins were very much ahead of their time for a ferry, it was not until over a decade later when other ferries would match the size and fittings of Finnjet's cabins. Her restaurants and other services were also superior to other ferries of her time. Finnjet's influence can be clearly seen on the first genuine cruiseferries built for Finland–Sweden traffic in 1980–81, ships such as MS Viking Song, MS Viking Sally and MS Finlandia.

Partially due to being such a ground-breaking ship, Finnjet was also extremely prestigious, which helps explain why she remained in traffic on the Baltic Sea for such a long time even though she was often unprofitable. Famous Finnish painter Kimmo Kaivanto provided paintings and drawings to decorate the ship, and he even designed a Finnjet medallion to commemorate the ship's commission. Kaivanto's main work for the ship, the three-deck high Pictures of Finland, was given to the Finnish Maritime Museum in 2007, destined for display in the museum from 2008 onwards. In 1977 a 7-inch single, "Finnjet Waltz", was recorded in honour of the ship, and she was the first ship ever to have a Lego model of her for sale on board. As late as the early 1990s Silja Line still considered Finnjet to be one of their greatest ships, and in their brochures she appeared right after the brand-new Helsinki–Stockholm ferries, ahead of many ships that were both newer and larger than Finnjet herself was. Finnjet still remains the best-known individual ship in Finland. She also has a very good reputation in Germany, and in August 2006, Silja Line's new owners Tallink went on record considering adapting the name 'Finnjet' for their Finland–Germany ferries (to the dismay of ferry enthusiasts in Finland and Germany). However Finnjet is a registered trademark of Finnlines (until 2017) and therefore Tallink could not go ahead with their plan.

In the beginning of the 1970s a study was made about the future development of passenger numbers on the ferry service between Finland and West Germany. The study projected notable growth, with 300,000 to 800,000 passenger projected to make a crossing in 1980, with the likeliest number projected at 500,000. At the time Finnlines and Finland Steamship Company were maintaining a joint service on the route with two ships built during the latter half of the 1960s (MS Finnhansa (1966) and MS Finlandia (1966), respectively), both capable of transporting a maximum of 100,000 passengers per year. Based on the estimates made Enso-Gutzeit, one of the owners of Finnlines, begun planning a new, larger and faster ferry for the service. Initial plans made in 1971 called for a ship with 800 passenger berths (the Finnhansa had only 300 at the time), but these were abandoned in favour of an even larger ship. The plans for the new ship, codenamed Finnjet, were developed within the next two years.

Project Finnjet was developed into a much larger ship than the Finnhansa or Finlandia. Finnjet was to have 1,500 passenger berths and the ship would be powered by two gas turbines instead of the traditional diesel engines. Gas turbines would give her a service speed of 30.5 knots (56.5 km/h; 35.1 mph) (compared to the 20 knots (37 km/h; 23 mph) of the Finnhansa), making it possible to cut the passage time between Helsinki and Travemünde from 36 hours to just 22 hours. Advanced loading systems developed for the ship meant her port turnaround time would be just two hours. These factors combined meant that Finnjet would have a yearly passenger capacity of over 300,000.

As a temporary measure to cover for the rising passenger numbers Thomesto Oy, another member of the Finnlines consortium, purchased the 1966-built MS Finnpartner (1973) and placed it in Finnlines traffic in 1973. On 5 December 1973 Enso-Gutzeit placed an order for project Finnjet with the Wärtsilä Hietalahti shipyard in Helsinki, Finland. The cost of the ship has been estimated at being between 200 and 300 million Finnish markka, making her the largest investment made to Finnish tourism by that time. At the time Finnjet was in fact planned as the first in a pair of identical sisters. The build contract included an option for a second vessel that was offered to the Finland Steamship Company as a part of the joint service agreement between Finland SS Co and Finnlines, but Finland SS Co decided not to utilise the option.