James Franco took to Instagram to congratulate brother Dave Franco and longtime girlfriend Alison Brie on their engagement. News of their engagement broke Monday. Dave, 30, and Alison, 32, have been together since January 2012, though they have been very secrative about their relationship.

James, 37, posted a photo of his younger brother and new fianceé on Instagram. The photo shows Alison and Dave walking hand-in-hand during a recent outing. In the caption he sent the couple his congratulations. He ended his message writing, "I WUUUUUV YOU." 

Dave and Alison have managed to keep a majority of their relationship underwraps. E! Online exclusively confirmed their engagement earlier this week. A rep for the couple shared the big news with the publication. The "Community" actress was recently seen wearing her enormous engagement ring late that same evening at a screening of "Sleeping With Other People." MTV reported that she proudly showed off her new jewlery, posing with her hand on her hip.

Pictures from the event show the former "Mad Men" actress sporting a multi-carat circular ring on that finger. The ring features a thin band and massive center stone surrounded by a circle of smaller diamonds. Exact dimensions and details about the ring have not yet been revealed.