The RLD will be contesting the elections along with the Congress. It will contest from eight seats in Uttar Pradesh.
Both Amar Singh and Jaya Prada were expelled from SP in 2010 for indulging in activities inimical to its political interests and damaging its image.
Singh had earlier dismissed speculations about his return to the party fold.
Making an announcement of joining RLD, Singh said that Uttar Pradesh should be divided to develop the region. “Development in UP is not possible without dividing it,” maintained Singh.