Paul Nassif -- I've Rebounded ... WITH A BEAUTY QUEEN!!

"Real Housewives of Beverly Hills" star Paul Nassif tells TMZ, he's only been dating his smoking hot 27-year-old beauty queen girlfriend for SIX WEEKS -- which squarely contradicts a report he was banging the girl while still with his wife Adrienne Maloof.

Reports circulated Paul has been dating former Miss Nevada USA Helen Salas since April last year -- four months before Paul filed for divorce in August.

But last night, as Paul and Helen arrived to The Ivy for dinner, the couple told us they only met 6 weeks ago ... several months after the divorce filing.

As for Adrienne ... she's also dating a much younger person -- Rod Stewart's 32-year-old son Sean Stewart.