The 26-year-old forward made just two top-flight appearances off the bench for the Saints following their promotion before a deadline day deal was struck to take him to the City Ground.
And, despite insisting that he happy to spend a year with Sean O'Driscoll's men, Sharp is seeking clarity over his situation at St. Mary's.
|14/1||Billy Sharp is 14/1 with William Hill to be the Championship's top goalscorer
"It's a massive club with a great fanbase and I am looking forward to playing for Forest."
Sharp, who bagged his only goal of the campaign thus far in Saints' League cup win over Stevenage, went on to express his excitement at joining Forest.
"Obviously I was only two games in and have only come on for a few minutes each game but I spoke to the manager and it was best of me to come here, so I'm delighted to be here," he added.
"From the short time I have been here I can see it's a good team spirit, there is good depth in the squad and there are some good players here."
Forest have made a blistering start to the Championship season, picking up eight points from their four games so far.