The Imps are delighted to announce the signing of former Burnley, Derby County and Norwich City centre-back Jason Shackell on a one-year deal.
The 34-year-old has just under 500 career league appearances, with the majority of them coming between the Sky Bet Championship and the Premier League.
Shackell has captained four of his previous sides, and has won promotion to the Premier League with Burnley, Norwich City and Wolverhampton Wanderers, while also being named in Championship Team of the Year in 2014.
The central defender becomes City's second signing on Deadline Day following the arrival of Spaniard, Joan Luque.
"There’s a lot of younger players in the squad and some really good experience here, but hopefully I can add to that and help pass on anything knowledge wise, or in tactics," Shackell said.
"That’s something I look to do. I like to help others where possible and help develop the squad that is already here."
Shackell had most recently been with Derby County, and spent the second half of last season on loan at Millwall.
The move to the Imps is the first time the former Barnsley captain has dropped below England's second tier.
"I think this is the right move for me. I’ve always played Championship or higher, but this club has been quite successful in the last few years," he added.
"It’s on the up and the management team and the staff all seem great when I spoke to them. I received a lot of positives and thrilled to be joining."
Shackell will wear the number five shirt at Sincil Bank, and is available for Saturday's Sincil Bank opener against Swindon Town.