Devlin will perform at the Whangamata Club with Sharplin & The Cadillacs tomorrow night with a special appearance by Shane Cortese.
The Repco Beach Hop 15, which began on Tuesday and runs through to Sunday, celebrates the best of 1950s and 1960s, Mr Watts said.
He has been involved in organising the event since "day one" - this is his 15th year as organiser.
"It's an absolutely awesome event, which just gets bigger and better every year.
"It's already going off. Whangamata is definitely the place," he said.
Mr Watts said vehicle entries opened on October 1 and sold out within 24 hours, with more than 1000 cars taking part in the beach hop, including 300-400 from the Western Bay of Plenty.
The grand parade through the town centre starts at 9.30am on Saturday, and culminates with six to seven shows, including the retro car and retro caravan shows.
"It's going to be massive."
There is also a tot-rod pedal car event, the Hop Idol competition, with former Police 10-7 host Graeme Bell and Cortese on the judging panel, he said.
The three-day Petrolhead Vintage Market at Whangamata Memorial Hall has always been a smash hit with Beach Hop visitors, and thousands went through the doors last year.
Legendary Pinup photographer Mitz & Co has come all the way from Southern California to treat beach hoppers to professional Pinup shoots. Mr Watts said last year 110,000 people attended the festival on Saturday, and he expected similar numbers to attend this year, if the weather co-operated.
"We have also got an American TV crew coming to film the Beach Hop, which will ultimately be screening on the Discovery Channel," he said.
Entry to the festival is free, but anyone who buys the $5 programme goes into the draw to win a share of the prize pool - either a 1950 Mercury car, 1969 Classic Caravan or $10,000 cash.