Cops arrested a 30-year-old man after the collision in the village of Pentre, Rhondda, around 1.30am this morning.
The victims were struck by a white Citroen Berlingo outside the Banc nightclub.
Police have sealed off the road as they carry out an investigation.
A South Wales police spokesman said: “We’re appealing for witnesses following a road traffic collision that occurred at approximately 1.35am [today] outside The Banc night club on Llewellyn Street, Pentre.
“A white coloured Citroen Berlingo vehicle collided with two pedestrians, both of whom are being treated at hospital, having received serious injuries. A 30 year old male driver was arrested at scene.
“The carriageway was closed for several hours whilst investigation work was carried out, and officers wish to thank members of the local community for their patience and understanding during the road closure.
“South Wales Police would like to speak with any witnesses to the collision, any person who may have dash cam footage of the incident, any person who may have left the area without giving information to Police or anyone who witnessed the manner of driving of the Citroen Berlingo prior to the collision.”
Anyone with information should contact 101 quoting number 1900207321.
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