The retailer, famous for its frocks, spring racing marquees and Jennifer Hawkins, has joined forces with singer Katy Perry to sponsor the Australian leg of her upcoming world tour.

As brands like Aje, by johnny and Self Portrait leave Myer to join David Jones, Myer is repositioning itself as a retailer keen to give customers "an experience and not just sell them stuff", chief executive Richard Umbers told Fairfax Media.

Umbers, a father of two daughters and "huge Katy Perry fans", made the announcement on Friday afternoon with Perry at the Sydney store in front of hundreds of screaming fans, some of whom had camped outside since 3am.

While he wouldn't be drawn on the total cost of the investment Myer will be making in the Witness world tour, Umbers said the decision to bankroll Perry's Australian show was his version of corporate carpe diem.

"Eventually you end up in a place where you think you've got to do this on a spectacular scale," he said.

"Retail these days isn't for the timid. You've got to really push the boat out. Retail now is internet-based and completely global, we have to be able to punch right up there and be able to compete with all comers."

"I haven't seen any other retailer in Australia do something on this kind of scale, with this kind of theatre. You can either be a 'me too' and follow the herd or you can get out there and do something that has got more impact and a real connection.

"Just to say you sell more is not where this is at now. Those retailers can do that but we're hoping to leave them behind and it's events like this that lift us out of the melee of sameness and banal retail."

This move toward music promotion is a huge marketing exercise for Myer, and a shrewd and cost-effective data-farming ploy.

Via its customer loyalty program, the department store will give away 8000 tickets to Perry's Australian shows, a year before the July 2018 tour.

Customers who sign up for the program and spend $120 in one transaction until July 29 will be in the running for tickets.

"When you spend your money, we have to know who you are to then be able to select the competition winners, so we need those details on file," Umbers said.

Something fans at the announcement were happy to hand over, and were doing on their smartphones as Perry greeted fans and took selfies.

"I don't shop here often but I'll find something to buy and get one of those cards for sure," Perry fan Jess McCormack told Fairfax Media. "I saw her exactly 930 days ago and I want to see her again."

Perry will join the Myer stable in September as a designer when her new footwear collection lands in stores around the country.

On Friday she didn't wear a pair from the range, something she "100 per cent designed", instead she opted for a blue leather ensemble and white heels by Alexandre Vauthier while eating Tim Tams and avoiding questions about her recent lacklustre record sales.