An attack submarine that is sponsored by first lady Michelle Obama and will be named for her home state has been delivered to the US Navy.

Submarine builder General Dynamics Electric Boat, based in Groton, Connecticut, delivered the submarine that will become the USS Illinois to the Navy on Saturday after nearly five and a half years of construction.

The first lady, who's from Chicago, will be involved in the life of the submarine and the lives of its sailors and their families.

The submarine USS Illinois travels along the Thames River after departing General Dynamics Electric Boat in Groton, Connecticut, for initial sea trials, where the ship's performance is tested prior to delivery to the U.S. Navy (July 2016 photo)

The submarine will officially join the Navy fleet in a fall 2016 ceremony

The submarine will become the USS Illinois, SSN 786, and begin its active service at a commissioning ceremony in Groton on October 29.

US Navy Secretary Ray Mabus said in a 2012 statement: 'Naval tradition holds that a sponsor’s spirit and presence guide the ship and her crew throughout the life of the ship.

'Illinois and her crew are blessed to have such a wonderful sponsor and I am grateful Mrs. Obama accepted my invitation to serve as sponsor for this submarine.'

The First Lady said in a 2012 statement: 'It’s an honor and a privilege to serve as sponsor of the USS ILLINOIS.

'I'm always inspired by the service and sacrifice of the men and women of the Navy, as well as the families who support them.

'This submarine is a tribute to the strength, courage, and determination that our Navy families exhibit every day.'

It took thousands of shipyard employees in Connecticut, Rhode Island and Virginia and submarine supply businesses nationwide to build the $2.7billion submarine, the 13th member of the Virginia class.

There were no major issues during construction, and the submarine performed 'superbly' during recent tests at sea, said an Electric Boat vice president, Kenneth Blomstedt.

First lady Michelle Obama christens the USS Illinois with a bottle of sparkling wine (October 2015 file photo)

The first lady, who's from Chicago, will be involved in the life of the submarine and the lives of its sailors and their families

Electric Boat president Jeffrey Geiger said in a August 1 statement: 'The crew and shipbuilders worked together seamlessly to take this submarine to sea and put it through its paces.

'It was a superb effort by everyone involved, and reflects the commitment of the navy and industry team to sustain the success of the Virginia-class submarine programme.

'I deeply appreciate the contributions made by the navy personnel, shipbuilders and suppliers who made it happen.'

Capt. Michael Stevens, the Navy's Virginia-class program manager, said these attack submarines are needed to replace those that were built during the Cold War and are retiring.

'Every submarine counts', he said. 'Every submarine is needed out there.'

It took thousands of shipyard employees in Connecticut, Rhode Island and Virginia and submarine supply businesses nationwide to build the $2.7billion submarine, the 13th member of the Virginia class

First lady Michelle Obama, right, and General Dynamics Electric Boat president Jeffrey S. Geiger, exit the USS Illinois after Obama christened the sub in October 2015

Electric Boat, which has been designing and building submarines since 1900, had until August 31 to transfer ownership of the future USS Illinois to the Navy, per the contract.

It's the ninth submarine in a row to be delivered to the Navy early and on budget, Stevens said.

The submarine has a redesigned bow with two large tubes to launch Tomahawk missiles, instead of 12 smaller tubes.

The larger tubes were designed so the Navy would have the flexibility to also launch future weapons and unmanned vehicles, Blomstedt said.

Cmdr. Jess Porter, the submarine's commanding officer, described the Illinois as a 'stealthy weapon' that can influence adversaries in a way that makes the US more secure.

The crew of about 130 men will take the submarine to sea for additional testing to prove its capabilities, Porter said.

Construction began in March 2011. Modules were built in Rhode Island, at Electric Boat's manufacturing facility, and in Virginia, at Newport News Shipbuilding.

The two shipyards build Virginia-class attack submarines under a teaming agreement and alternate the deliveries. The final assembly and testing took place at Electric Boat's headquarters in Groton.

Construction began in March 2011. Modules were built in Rhode Island, at Electric Boat's manufacturing facility, and in Virginia, at Newport News Shipbuilding

Obama, who has made it a priority to support military families, broke a bottle of champagne across the submarine's hull to christen it last year.

She has been invited to give the order to 'bring the ship to life' at the commissioning ceremony in October.

Inside the submarine, there's a metal plate inscribed with the first lady's initials, which each sailor will see several times a day. It's mounted where the crew eats.

The Navy has ordered 15 more Virginia-class submarines, and 10 of those are under construction. The last of the 15 is scheduled to be delivered in 2023 as the 28th member of the class.

General Dynamics said in a August 1 release: 'Virginia-class submarines displace 7,835 tons, with a hull length of 377 feet and a diameter of 34 feet.