She might not be the first Mrs Reynolds – Ryan was previously married to Scarlett Johansson – but the spectacular $2 million sparkler showed without doubt Blake is his number one girl.
Blake was back on the Gossip Girl set this week without her ring, but the diamond was spotted the day after the couple's September 9 wedding as they canoodled at the Boone Hall Plantation and Gardens in South Carolina, where their low key nuptials took place.
Ryan enlisted the help of celebrity jeweller Lorraine Schwartz to help him find the perfect jewel for his bride-to-be.
The flawless pink oval diamond was set in rose gold and pave diamonds with a nod to art deco, and Ryan was heavily involved in the finished design.
As well as the engagement ring nobody knew about, Blake was also wearing her brand new wedding band.
Also made by Lorraine, it featured a delicate row of diamonds set in rose gold.
While fans still wait to see photos of the couple's big day, their wedding planner has been revealing details from their intimate ceremony, which was attended by 60 people.
"Ryan and Blake wanted the event to look and feel like home. We created the charm, elegance and magic of times past. It was a truly elegant celebration," Tara Guerard told US publication People.
A source revealed the pair had a retro-carnival theme, with popcorn served in paper bags with their initials.
"They're a fun couple who wanted to inject that into their wedding," said the friend.