Every gal has her flaws — even Rihanna.

The usually stunning songstress was caught in an unflattering pose on Monday night after partying at Mahiki, a nightclub in London. As she climbed into a limo, photographers caught a glimpse of her too-short skirt — and a bit of cellulite.

But the “Good Girl Gone Bad” has at least one male admirer who doesn’t seem to mind her imperfections: Spies tell us that the singer is dating actor Tristan Wilds. The “90210″ star was an unexpected guest at a party RiRi held over the weekend at her L.A. home, where she was saying goodbye to pals before taking off for a set of London gigs.

“No one knew why Tristan was there initially, because it was not an industry party — it was very intimate,” says a fellow guest. “But everyone quickly realized they weren’t meeting for the first time, because they were openly affectionate for everyone to see.”

Our source adds that 21-year-old Rihanna and the 20-year-old actor, who has also starred in “The Wire” and Jay-Z’s “Roc Boys” music video, were introduced by a music producer who has worked with both of them — Wilds is currently working on an album of his own.

They hit it off the moment they laid eyes on each other, the insider says. “He’s a real gentleman,” says the source. “She likes him a lot, and it shows. From the moment he walked into her party, Rihanna lit up.”

So what now? Although RiRi will be traveling to promote her album “Rated R,” which drops on Monday, our source thinks the fling will last.

“They’ll keep in touch while she’s away,” the snitch insists. “They’re already planning to use iChat and Skype to stay in contact until Tristan finishes shooting ‘90210′ for the season and can fly out to meet her on the road.”

While that may be the case, Rihanna may want to ask her new beau why he’s palling around with her ex, Chris Brown — on Twitter, at least. On Sunday, Brown tweeted that he was “so tired.” Shortly thereafter, Wilds took to his page to give the singer some words of encouragement. “Keep grinding, kid. All we can do,” he wrote.

Let’s hope Rihanna straightens out that issue ASAP — along with her wardrobe.