The former Toon striker continued his impressive return to form and fitness with two goals in Tuesday's friendly win over Peterborough.
Curbishley: "He has been working ever so hard.
"Obviously he finished the season and got himself fit at the end of season so he has had a bit of a run at it and maybe he has a little bit longer than perhaps the others.
"It is great for us. It is just like a new signing coming back.
"Dean Ashton scored a couple the other day and now Craig Bellamy has come back and got a couple of goals so it is terrific for us."