The red-shirt rally will be held at Khao Talo, opposite the Big C Supercenter and Tesco Lotus in South Pattaya.
Mrs Tida said the gathering was intended for red-shirt supporters in Eastern Thailand, where the UDD had never held an event before. The UDD has its stronghold in the North and the Northeast of the country.
The UDD is also expecting supporters from the West in provinces such as Kanchanaburi, Phetchaburi and Ratchaburi, who will gather on Rama II Road in the Bang Khun Thian area before proceeding to Chin Buri. Supporters from provinces including Chachoengsao, Nakhon Nayok, Sa Kaeo and Prachin Buri will meet at the North Pattaya motorway exit.
The gathering will start at 6pm and is scheduled to end at midnight.
Last Saturday, the red-shirts held a major rally in Ayutthaya province. They used the event to step up their attacks on the courts and independent organisations, which they believe are no longer neutral and are working to oust the Pheu Thai caretaker government.