Holiday engagement for Tom and Gisele?

Are Tom Brady and Gisele Bundchen finally engaged? We’re hearing through the grapevine it’s true.

Gossip site TMZ kicked off the buzz this morning, reporting the injured Patriots QB proposed to his supermodel girlfriend of two years on a private flight from Teterboro Airport in New Jersey to Boston on Christmas Eve. Her parents were reportedly along for the ride, along with four dozen white roses and some bubbly. The site reports Brady was nervous before he popped the question, but – of course – Gisele said yes.

A source close to Brady said he heard the engagement is a go.

Photographers staked out Brady’s Back Bay home today, hoping to glimpse the couple, members of their families, or even some sparkle on Gisele’s left hand. At 3:45 p.m., a black Audi A8, driven by Brady's assistant Will McDonough, pulled up to the back of Brady's Beacon Street home, and out jumped Gisele's mother, Vania, followed by an unidentified man. After a short time, McDonough re-emerged and drove off.

Tom Brady was at the Patriots' training room at Gillette Stadium yesterday, but decided not to go into the locker room when he spotted reporters.

The engagement story wasn’t a huge surprise, as the web has been abuzz recently with reports that the couple has been out ring shopping and planning a small March wedding in Costa Rica, where Gisele has a vacation home. That said, gossip hounds have weathered plenty of false alarms in Brady-related nuptial news.

Officials at both airports were unable to confirm the lovebirds’ flight, and Pats spokesman Stacey James is mum, as usual.

“Long ago I stopped going to Tom with items of personal interest, after the number of houses he’s bought and how many times he’s been married,” he joked. (Brady has never been married, to anyone’s knowledge.) “I’m sure when the time comes that Tom wants the world to know these kind of details, he’ll let everyone know.”

Brady’s agent and family could not be reached for comment.

The Brady-Bundchen romance kicked off scandalously in late 2006, after Brady split with his pregnant former flame of nearly three years, Longmeadow actress Bridget Moynahan. Before the baby-mama drama, the Pats star had a squeaky clean, good-boy image, and many predicted he and Moynahan were altar-bound. (Bundchen was also coming off a long relationship with actor Leonardo DiCaprio.)

Brady and Bundchen immediately began canoodling around the globe, even as a reportedly shell-shocked Moynahan worked through her pregnancy solo in California. Since the birth of son Jack in August 2007, Moynahan and Brady appear to be parenting together, and the little guy has even been spotted out and about with dad and his potential future stepmom.

After blowing out his knee this fall, Brady’s had plenty of quality time for Bundchen – so much so that he’s become a paparazzi punching bag for doing her errands and walking her dog. (TMZ particularly loves harassing and filming the QB as he gimps from Gisele’s NYC townhouse door to his car.)

The latest is that the couple laid down about $11.7 million for property in a gated community in Brentwood, near the estate of California Gov. Arnold Schwarzenegger. Moynahan, who happens to be filming a TNT cop drama in Boston with Donnie Wahlberg, also calls the West Coast home, as does Brady’s family. The theory goes that Brady and Bundchen hope to build a home closer to baby Jack.

PAYSHA RHONE