Hush-Hush Hookup for Jake Gyllenhaal and Rachel Bilson?

Wonderwall, Thursday, September 9, 2010, 10:53am (PDT)

By Kat Giantis

The rumor mill is trying its darnedest to make Jake Gyllenhaal and Rachel Bilson happen. Two weeks after romance rumblings first surfaced (and were pooh-poohed), the respective exes of Reese Witherspoon and Hayden Christensen are once again being declared an item.

"They're trying to keep a low profile, but they're definitely dating," a source assures Hollyscoop.

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The Chicago Sun-Times echoes that the dark-haired pair, who were spotted dogward-dogging in the same yoga class late last month in Los Angeles, are "quietly" seeing each another.

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Bilson, 29, who we secretly hope will one day reunite with former "O.C." love interest Seth Cohen Adam Brody, recently confirmed that she'd pulled the plug on her year-plus engagement to "Jumper" co-star Christensen.

Gyllenhaal, 29, has been flying solo since his two-year relationship with Witherspoon ended in December 2009.

But don't get your hopes up for Jake and Rachel to become a leading contender for Hollywood's most adorable new couple.

"They have not and are not dating," the actress's spokesman insists to Wonderwall.

Jake's rep concurs, telling us, "These reports are false."

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