Boss Brendan Rodgers revealed his delight after skipper Scott Brown and Jozo Simunovic signed new deals with Celtic on the eve of their Champions League clash with Paris St Germain.
The Parkhead club confirmed that 32-year-old Scotland captain Brown, who joined the Scottish champions in 2007, has penned a two-year contract which takes him until at least 2019.
Defender Simunovic, 23, who arrived in Glasgow from Dinamo Zagreb in 2015, has penned a new four-year deal until at least the summer of 2021.
Rodgers is preparing for the visit of free-spending all-star French side PSG in their Group B opener where he will have Leigh Griffiths back after a calf injury but will still be without fellow striker Moussa Dembele as he works his way back from a hamstring complaint.
However, he confirmed the boost the Hoops squad will get from two players happy to extend their time at Celtic.
"I am delighted for both," he said. "Scott has been a great captain here over many years and certainly in the period I have been here, he has consistently played at a very high level.
"We were talking towards the end of last season and it was a case of just getting the Champions League qualification out of the way and hoping to get something agreed.
"So I am absolutely delighted because he is a very important figure for us on and off the field and I have been delighted at his performance level and how tactically he has been playing the game.
"Jozo is a young player that, obviously there was a focus on his injury past, but this is a great arena for him to play and he is in an environment where he needs that development and once he is fit and trains and plays consistently he is an outstanding talent.
"So it is great news for our squad because we are trying to build and create something here.
"A lot of our players now are tying into longer deals, which is great.
"It is a really exciting period and we have one or two others that we will look at to try to ensure the squad remains as stable as possible whilst looking to progress at the same time."