Ryan Reynolds turned 35 on Sunday, and who was by his side, celebrating with him? None other than his 24-year-old ‘Green Lantern’ costar, Blake Lively.

Early Saturday morning, the two were photographed leaving his Boston apartment. (He is in town filming ‘R.I.P.D.’)

The couple made their way to a waiting SUV along with their dogs, Baxter (his) and Penny (hers).

Later that day, Lively was seen attempting to hoist a heavy, brown-paper-wrapped package during a visit to the “R.I.P.D.” set, leading to speculation that she personally delivered Ryan’s birthday present.

Snappers also caught the PDA-disposed pair (and their pooches) leaving Reynolds’ pad on Sunday morning.

Both stars attempted to dodge the lenses, with Blake styling a floppy hat pulled low over her eyes and Ryan, who perfected his shutterbug-avoidance technique while married to Scarlett Johansson, trying to hide his face behind his leather jacket.

“They are very much a couple,” an insider tells People. “They’re really happy together.”

But an Us Weekly source is not quite as enthusiastic, downplaying, “They’re seeing each other casually. Now they’re both single and trying it out.”

Still, Ryan is apparently serious enough about Blake to introduce her to his longtime friend (and sometime co-star), Sandra Bullock. The trio met up for a group dinner last Thursday in Manhattan, says the New York Post.

“He and Blake were being really cute and affectionate together,” relays a spy, who says Lively and Bullock both offered an early birthday toast to Reynolds.

After dinner, the birthday action moved to hot spot The Box, where the passel of pals enjoyed a tongue-in-cheek burlesque act that included an homage to “Deliverance.”

“Sandra arrived with the couple and a group, and they watched some of the burlesque performers,” says a snitch. “The group had a great time and stayed late. Sandra left with many of the others, leaving Blake and Ryan alone.”

Chimes in another onlooker, “Blake and Ryan were sitting downstairs holding hands and had bodyguards with them. They left together at around 2:15 a.m.”

Source, Photos: Fame