The Welshman said: "This will be the greatest year ever for Welsh sport if Cardiff lift the cup.
"The rugby lads won the Grand Slam, I beat Bernard Hopkins in Vegas and now it is down to Cardiff to do the business.
"It is unbelievable to see them in the Cup final and the buzz is like one of my big fights - all the talk is of the big match.
"They have got a good, solid team with experienced players - such as Robbie Fowler and Jimmy Floyd Hasselbaink - and some good, young talent like Aaron Ramsey.
"I saw Joe Ledley's stunning goal against Barnsley in the semi-final and really rate him. My prediction is 1-0 to Cardiff.
"This is the equivalent of a world championship title fight for Cardiff . . . so come on you Blues!"