Academy graduate Sid Nelson has extended his stay at Millwall by signing a new contract until the summer of 2019.
The 22-year-old, who joined The Lions' Academy aged eight, signed his first professional contract in 2014 after captaining the youth team.
He went on to make his Sky Bet Championship debut in December of that year and nailed down a place in the Millwall side.
The centre-back spent two further seasons in the heart of Neil Harris’ backline before gaining experience on loan in the last two years at Newport County, Yeovil Town and, most recently, Chesterfield.
Speaking to millwallfc.co.uk Nelson said: "It's been 18 months of development for me. I've changed as a player since I was last here.
"I can't wait to get going now and prove to people I have changed and got better as a player and a person. I'm honoured to have another year back at this club.
"I feel like I've grasped my opportunity out on loan, and I'm grateful to have the opportunity to put the Lion on my chest again."
Harris remains confident that Nelson can forge himself into his first team plans adding: "We believe he has a long-term future at this football club.
"He knows we believe in him. We were really pleased with his performances at Chesterfield. Far too much came to him too early at this football club.
"We need to remove that expectation from him and let him develop how he should be able to develop."