Young people line up to take selfies with him. His hashtags are trending. And when billionaire Thanathorn Juangroongruangkit promises an end to Thailand's military "dictatorship," supporters of his Future Forward Party roar their approval.

The 40-year-old heir to an auto parts fortune is a political newcomer and social media star who has energized young voters ahead of March 24 elections, the first since a coup in 2014.

"I urge our 'Futuristas' to campaign against the future in which the junta leader comes back as a prime minister," Thanathorn said at a rally on Saturday.