The 19-year-old has been discussing both himself and the Bhoys' new signing.
The teenager spent the second half of last season with the Norwegian club but has returned to the Hoops ahead of the new campaign.
Henderson has already featured for Celtic in pre-season but the midfielder admits he needed time away to truly appreciate what he has at Parkhead.
Indeed, the 19-year-old says living alone while at Rosenborg made him realise how much it means to play for Celtic.
LH on how he became a better person: "Living by myself and realising what I have back here. Maybe I took it for granted a bit." (MH)— Celtic Football Club (@celticfc) July 8, 2015
LH: "Out there I realised how much it means to play for Celtic and how much I want to do well here. Delighted to be back." (MH)— Celtic Football Club (@celticfc) July 8, 2015
Meanwhile, Henderson is also looking forward to playing alongside new signing Nadir Ciftci, who was confirmed on Thursday afternoon as Celtic's new forward.
The 19-year-old was speaking before the confirmation of the move but still gave a positive verdict, suggesting he 'would' be a great signing, having played against him in the past.
LH on Nadir Ciftci: "He would be a great signing. Played against him a couple of times. A strong guy and scores goals." (MH)— Celtic Football Club (@celticfc) July 8, 2015
The season ahead could be a big one for both players, with Henderson likely to at least be given another chance on loan if he can't break into the matchday squad, while Ciftci will have to deliver after all the attention his Celtic move has received.