Cook revealed his delight at Pietersen's return on Wednesday and Finn admits that Pietersen's presence provides the team with a big boost ahead of the winter tour of India.
The Middlesex bowler told Sky Sports News: "It's excellent to have Kevin back, I'm glad that everything's been sorted out.
"It's great to have someone of his calibre in our team going into this tour to India.
"He's going to be a great help for us over there. He's experienced a lot in Indian conditions and, as he always does, he will transfer his knowledge to everyone else in the group."
The squad left for Dubai on Wednesday to begin preparations for the series.