Thai King Bhumibol Adulyadej on Monday endorsed the election of Yingluck Shinawatra, 44, as the country's first female prime minister, paving the way for a new cabinet, according to dpa. Yingluck, the youngest sister of former premier Thaksin Shinawatra, was elected prime minister by the House of Representatives on Friday, but under Thailand's constitutional monarchy her post did not become official until endorsed by King Bhumibol, 83, who is head of state. In a ceremony at the Pheu Thai party headquarters, Yingluck kneeled before a portrait of the king, to acknowledge the royal endorsement. Earlier Monday, Yingluck said her cabinet list was 80 per cent completed and would be ready to submitted to the king for endorsement within two days. The prime minister faces a host of ugly challenges, not the least of which will be how to handle public relations for her big brother, former telecommunications tycoon Thaksin, who was prime minister between 2001 and 2006. Thaksin has been living in Dubai to avoid a two-year jail term on an abuse of power conviction.