Samsung Electronics, the world's top smartphone maker, gave a glimpse of new square-shaped foldable phones in a surprise TV commercial aired during the Academy Awards last night. 

The ad, broadcast only in the US, comes two days before its Galaxy Z Flip phones, which open and close vertically like a flip phone, are due to be unveiled at an event in San Francisco. 

While there were many shots of the phones, which come in at least purple and black, there were few other details. 

They are, however, expected to be less expensive than the $1,980 Galaxy Fold which opens like a book and was launched in September, delayed by several months after problems with its screens. 

"The new Galaxy Z Flip foldable phone will create a halo effect for Samsung's brand and help it better compete with Apple's pricey models," said Tom Kang, an analyst at research firm Counterpoint.

He added that Samsung had taken the lead in foldable phones at a time when Chinese rivals looked set to leap into the nascent market.