The 50-year-old Australian actor - who has played the role of Paul Robinson since the soap began in 1985 - was invited to the annual ceremony to present the best villain award, this year won by Coronation Street's Gray O'Brien (Tony Gordon).
The unknown Neighbours obsessives, who apparently looked like characters from Little Britain, purchased their passes to the event for £250 from eBay and began taking anything and everything that Dennis touched, including his drinks and snacks.
A source told DS: "They had access-all-areas passes and literally followed Stefan around the awards all night. They heard that he was flying over and when he confirmed his attendance at the BSAs on This Morning, they bagged their tickets for about £250 from eBay."
They added: "The pair only turned up at the awards to see Stefan and they took full advantage of his presence, lifting everything he touched – his drinks, plate of snacks and even the best villain card which he read from."
The mother and daughter duo also managed to secure the best seats in the greenroom to watch the ceremony on the large plasma TV.
Another source added: "They were all over ex-EastEnders actor Rob Kazinsky all night at one point, too."