The 24-year-old left Molde earlier this month to make the move to St Mary's after rejecting the chance to have a trial at Liverpool.
The Norwegian centre-back admits that his old boss was keen on persuading his compatriot to make the switch to England.
"For me [Solskjaer] has meant everything to me, he is a great coach and I have taken big steps because of him," said Forren.
"I spoke a lot to him about the move and he really wanted to give me this opportunity so I have to thank him for that.
"I haven't spoken to him in the last week but maybe I will give him a call soon. He thinks it is a good step for me and a club on the way up."
Forren is yet to appear for the Saints.