Their tandem jump will be part of a celebratory open day offering $88 jumps for people wearing 1980s fashion. There will also be stunt jumping displays, a sausage sizzle and a DJ from 9.30am until 3pm.
Five hundred primary school children have been invited to the bridge to join in the party.
Mr van Asch said he was thrilled hundreds of schoolchildren would be coming to the bridge to help celebrate the anniversary.
"These kids have grown up with bungy, but it's still a challenge for them. They're still motivated to want to do it.
"When I stand out there with A. J., I know we are still both as passionate about it as we were then. It has been a fantastic ride and we're both really happy to have done something that's been fulfilling for all our jumpers and crew from all around the world, for Queenstown and for tourism."
Wakatipu residents are also invited to A. J. Hackett Bungy's 20 Years of Bungy Birthday Bash on Friday. Jordan Luck, former frontman for the Exponents, plus Tahuna Breaks and Rockquest runners-up the Slur Tones, from Mt Aspiring College in Wanaka, will perform on stage at Queenstown Memorial Hall from 7.30pm. Tickets cost $20 and are available from A. J. Hackett Bungy Centre on Shotover St.
Mr van Asch said he was also looking forward to the birthday bash.
"A. J. Hackett Bungy parties have always been pretty legendary, but this is a real landmark for us and we'd love absolutely everyone to help us celebrate. So many people in the community have been involved with bungy over the last 20 years in some way, shape or form - whether it's been working for us, jumping, bringing in visitors, supporting our events and so on - that we want to show our thanks.
"I'm also looking forward to catching up with hundreds of former staff who are coming from all around the world. We've had close to 2000 people work for us over the past 20 years and I can't wait to see who turns up."
