Twomey and Matthews re-sign for Harlequins
"The Club is incredibly fortunate to have two players of Charlie and Sam's ability who still have so much growth and potential in them at 24 and 23 respectively," Harlequins Director of Rugby Conor O'Shea said.
"Alongside the other tight five forwards at the Club I am sure they will learn and thrive from the presence of James Horwill and these two young men will be the corner stone of this club for years to come."
Charlie Matthews joined the Harlequins Elite Player Development Group at the age of 15 and split his time in the senior Academy set up by studying a foundation degree in Sports Science and Sports Management at Loughborough University.
The former England Under-20 player made his senior Harlequins debut in November 2009 and has gone on to make 101 appearances. He played in all of Harlequins' 18 Premiership matches in 2015, more than any other player in the squad.
Following an impressive 2013/14 campaign, the former Hurstpierpoint College schoolboy was called into England's XV side to face the Barbarians at Twickenham Stadium in May 2014.
Commenting on the news, Matthews said: "I'm delighted to have committed to Harlequins, a Club I've been associated with for ten years. To have made my 100th appearance recently was a huge honour and I'm looking forward to continuing to learn and develop as part of this incredibly talented group for the coming years."
Sam Twomey joined Harlequins' Academy set up through the Sussex developing programme having begun playing at Crawley RFC. The six foot six second row has represented his country at every age grade level and made his senior Harlequins debut in 2011 against London Irish. Since then, he has made 37 appearances for Harlequins.
Having made a positive start to the 2015/16 season, Twomey sustained an injury against London Irish last month. Following a successful surgery, he is expected to return in March.
Twomey added: "Harlequins is a club that strives to be successful every year and to be a part of that is something special. The Club stands by its players and helps them progress to become the best they can be. I'm really pleased to have re-signed."