"Joshua is capable of unifying the division, absolutely."
Joshua made headlines around the world with his title defence against Klitschko at Wembley in April, in a thrilling encounter which saw both men hit the canvas.
"It was an incredible fight," Klitschko said. "It doesn't feel like a loss. I won a lot of respect that I had never had even when I won my world titles."
Joshua, who has attracted massive support in the UK for his style and power, stopped Takam in Cardiff last month.
Joshua currently holds the IBF, WBA and IBO titles, with 25-year-old Kiwi Joseph Parker holding the WBO heavyweight title and American Deontay Wilder, 31, holding the WBC belt.
Echoing Klitschko's opinion, Andy Ruiz Jr, who Parker beat in Auckland for the vacant WBO title, also believes the advantage is with Joshua in a potential unification bout, but the Parker camp are sure Joshua has flaws, including what they describe as a "glass jaw".
The 28-year-old Britton's camp has made the first step in trying to achieve the feat which was last achieved by American Lennox Lewis, whose reign ran from November 1999 to April 2000.
The Herald understands Joshua's camp have agreed to a deal to have him square off against Parker and the bout is soon to be announced.