Running sporadically around the banks of the old canal, the Jack Russell terrier grabs his favourite toy, a rubber bird, tearing it from side to side.

He finally brings it back to his partner, Sarah McDougall, who promptly throws it into the water, with Forrest not far behind. The canine clears about 10 feet of air before splashing into the canal.

It's a performance that's received international attention. Forrest and Sarah, 14, recently plunged into prime time, diving on the Late Night with David Letterman show, splashing into a pool in Times Square in front of an audience of hundreds.

"There was a lot of people," said Sarah. "It was really fun."

At the taping in New York City on Aug. 4, Forrest made dives of 20 feet repeatedly, outdoing his competitor, comedy superstar Seth Rogen, who joined in the fun and made a dive of 17 feet.

But 20 feet is just average for the dog, who stopped by the Ed Sullivan theatre while touring the dock-diving circuit. Forrest, who is five years old, came in fourth at the qualifier for the 2008 Purina Incredible Dog Challenge, the Olympics of canine competitions, which took place in Augusta, New Jersey, on Aug. 2 and 3.

"The dog ahead of us, we were going to beat him, but his head was that much bigger," said Sarah

But Forrest still has more left in the tank. He leaves this weekend for the Splash Dogs gathering in Michigan, before hitting Carrot Fest in Bradford, Canada's top dock-diving competition.

The terrier does have a reputation to maintain. He is the No. 1 rated featherweight in North America in the Ultimate Diving Dogs division.

Diving is Forrest's passion, said Sarah.

"We found it was an inclination when we opened the car door and he just jumped off the dock on his own," said Sarah.

Forrest become a member of the McDougall family last year through Jack Russell Rescue Ontario. But he might not be with the family as long as they'd like.

Forrest has been diagnosed with stage five lymphoma. Since they've found out, the McDougalls have raised almost $2,000 for canine cancer research.

Through all the celebrity, Sarah herself has managed to keep a straight head.

"The other day my friends played a joke," she said. "We were all supposed to go swimming, but they were going to go across the street and say 'There's the girl from Letterman.' "