The pair were in Glasgow for the Our Hero awards when Reid approached the Celebrity Big Brother winner's table, the Sunday Mirror reports.
They apparently passionately kissed, before he "whisked" her upstairs at the hotel hosting the event, carrying several bottles of wine with him.
"They just could not keep their hands off each other," a witness told the paper.
"Alex was pawing at her and she was enjoying every minute of it. He bit playfully at her bottom and grabbed her face before they began kissing."
Reid was rumoured to be dating X Factor star Katie Waissel after insisting that he "wouldn't want another Katie Price type".
Houghton admitted last month that she was "devastated" by her break-up from TV presenter Rav Wilding.