Hundreds of people braved the rain to queue outside H&M's central London stores from the early hours in the hope they would be allowed in to the Jimmy Choo shoe section.
From 9am the shops, which usually open at 10am on Saturdays, opened the doors to customers in staggered stages.
There were lots of smiling faces carrying shiny purple Jimmy Choo-branded bags as they emerged from H&M in Regent Street.
Others were weighed down with three or four bags in each hand, sparking suggestions that online auction site eBay will soon be flooded with Jimmy Choo accessories from H&M.
Sara Parkinson, 30, was keen to add to her existing - more expensive - Jimmy Choo collection so she arrived at 6.45am.
"It was an absolute frenzy this morning," she said. "It was supposed to be controlled but in the end they just let everyone in.
"Once inside they were very good though and the staff were brilliant."
Mrs Parkinson, a town planner from Streatham, south London, said she already owned four pairs of Jimmy Choo shoes which cost her around four times as much as the H&M version.
"It was absolutely brilliant," she said of today's shopping experience.
"I bought two pairs of heels - a black pair and a zebra print pair - which were £80 each," she said.
"My first pair of Jimmy Choos cost me £420 so in comparison it's very good.
"Shoes are about how you feel and Jimmy Choos make me feel like I'm in Sex And The City."
Lucy Venn travelled by bus from her home in Hackney, east London, to join the queue at 4.30am.
Sheltering from the wet and windy weather under a shop awning in Regent Street, she waited until 9am to buy the £100 Jimmy Choo leather leggings she wanted.
The 23-year-old paralegal said: "I didn't care that they were Jimmy Choo really, I just love leather leggings.
"I think most of them have sold out already.
"I bought two pairs of shoes for £80 each as well as I had got there so early.
"It was worth it - I think it's great that H&M are doing this."
She said that, while there were no cat-fights in the queue, there were signs of obsession.
"It was funny listening to the conversations," she said. "There were some crazy people. Some said they were going to buy everything and were really stressed out about getting in.
"I have also never heard so many conversations about X Factor and Robbie Williams going back to Take That."
One committed shopper flew to the capital from her home in Newcastle to join in the clamour.
Although she found out the north-eastern city's H&M was stocking the collection after arranging her trip, student Rachael Blakey, 19, said she thought there would be more choice in the capital.
She said: "I had heard about the collaboration so I booked flights to come to London this weekend."
Miss Blakey arrived in the West End at 7.45am and, although she was allowed inside soon after 9am, she was not early enough to be allocated an early slot for the accessory section.
"I have just bought Jimmy Choo clothes so far," she said. "I really wanted the leopard-print high heels but because I wasn't in the first 150 I have to come back later."