Tom Brady Hits David Beckham Birthday Party

NIGHT ON THE TOWN BACKGRID

UPDATE

1:50 PM PT -- TMZ Sports has learned the mystery woman is ex-NHL player Tie Domi's wife, Heather ... and it doesn't sound like they're an item in the slightest -- considering the former Toronto Maple Leafs player was present for the bash, too.

Brady and Domi go back ... and they even hit the ice together in 2024, with TB12 playfully beating up the longtime enforcer during a workout.

Tom Brady appears to have a new love interest in his life ... the NFL legend took a brunette to David Beckham's birthday party over the weekend.

Gisele Bündchen's ex-husband hit DB's bash at the Cipriani Downtown Miami in Florida on Sunday with the mystery gal ... and while there…