Red carpet glamour came under attack by what might indeed be Decepticons as heavy downpours suddenly put a dampener on the proceedings. Many fans rushed for shelter while others stayed put under umbrellas.

Co-star Stanley Tucci, who arrived after Walhberg, was forced to walk down the red carpet under the protection of a black umbrella.

Earlier, at around 5pm, leading lady Nicola Peltz arrived in a revealing turquoise floor-length dress wearing her blond hair down. She was followed by director Michael Bay, Hong Kong actor Ray Lui – one of the film’s cast members – and mainland actress Li Bingbing.

It was the first time that Hong Kong has hosted the world premiere of an international blockbuster. The premiere kicked off at 6.30pm, and will be followed by an after-party outdoor concert with Grammy-award winning American rock outfit, Imagine Dragons.

The film was partly shot in Hong Kong and mainland China, where the premiere was initially tipped to be held. Industry insiders say film company Media Asia switched the venue of the premiere to Hong Kong after overseas journalists had trouble securing travel visas to the mainland.

Jorden Bhavnani, 13, a student at YMCA of Hong Kong said she and her friends came to see the red carpet show after a day of school exams.

“It’s amazing. I didn’t think I’d ever have celebrities like this so close to me. I’m really excited to see Mark Walhberg. Hong Kong hasn’t had this type of thing before.”

US Grammy-winners Imagine Dragons drew a large following of loyal fans ahead of their rooftop concert at Ocean Terminal car park scheduled after the premiere.

Some fans tried to gain access to Ocean Terminal car park as early as 2pm in the hope of getting the best spots in the all-standing concert set against the the backdrop of Victoria Harbour.

Watch: Stars arrive at red carpet premiere in TST

Jodie Lam Weng-san, 21, a student from Macau skipped the red carpet and began queuing for the concert at a stairwell blocked by security at the car park area just under the rooftop. “They were great last time I saw them in Germany,” she said.

Filming in Hong Kong lasted for ten days last October across a variety of locations, including Quarry Bay, To Kwa Wan and government headquarters in Tamar. It was understood that the government provided unprecedented support for the filming of the latest franchise.

Despite the blackmailing drama – where an air-conditioning technician was jailed after attempting to extort HK$100,000 from director Michael Bay for location fees – Bay said in a recent interview that he had a great experience in Hong Kong. “Hong Kong is a very visual city,” he added.

Hong Kong Tourism Board chairman Peter Lam said using Hong Kong as a location for international films and staging premieres helped boosted the city’s appeal worldwide. Other blockbusters shot in Hong Kong included The Dark Knight (2008) and Contagion (2011). Director Michael Mann’s upcoming film Cyber was also shot in the city last year.

“We are extremely happy and very proud,” said Lam, who is also the boss of film company Media Asia. “In recent years, we have seen a number of big-budget Hollywood action blockbusters shot in Hong Kong. These films are not only visual treats for filmgoers. They also put Hong Kong on the big screen around the world.”