Credit: Splash News Photo: Jessica Biel and Justin Timberlake at a Costume Institute Gala on May 3, 2010

On-again-off-again couple Justin Timberlake and Jessica Biel are not just friends with benefits, according to Lainey GossipJustin reportedly sealed the deal on Monday night when he proposed to his 29-year-old girlfriend at the Amangani resort in Jackson Hole, Wyoming.

After getting wind of the so-called engagement, a Jackson-based jewelry company posted the following message on their Facebook page:

"Word on the street is that Justin Timberlake proposed to Jessica Biel at the Amangani last night. We're picking out post-engagement presents for them just in case they come in! Trying to play it cool."

Back in New York, some PR dude named Kyle Schaffler tweeted, "Hehe, I love that NO media outlets know about the Justin Timberlake and Jessica Biel engagement. Benefits of working in PR."

And where'd Kyle get the news from? Some other PR person named Marina Lodato, who tweeted, "Paparazzi better head up to Jackson Hole! JT proposed!!!!!!!"

Hmmm, sounds a little sketchy to us, but we'll keep you posted as more news trickles in … from people not named Kyle Schaffler or Marina Lodato.  

UPDATE: Us Weekly is now reporting that Justin and Jessica did indeed get hitched in Wyoming. According to the magazine, multiple sources confirm the Amangani resort proposal story, with one insider saying that Justin "knew it was the right time to propose."

Source: Lainey Gossip, Us Weekly