Former Prime Minister Ranil Wickremesinghe, who is expected to take oaths as a Parliamentarian this month, will have a seat next to JVP Leader Anura Kumara Dissanayake.
Wickremesinghe will be the UNP's nominee for the party's single parliamentary seat secured at the last parliamentary election. The Working Committee unanimously approved Wickremesinghe's appointment to Parliament last month.
UNP sources said Wickremesinghe would take oaths as an MP in Parliament before the fourth week of June.
His entry into the House is likely to send ripples across the main opposition camp, as a section of MPs are dissatisfied with Sajith Premadasa's style of leadership.