Sandra Bullock and Ryan Reynolds enjoy dinner with friends in Wyoming

The Proposal costars were seen hiking last weekend in the Grand Teton National Park in Wyoming , with Ryan holding Sandra’s 1-year-old son Louis on his back.

But despite the many rumors of a possible relationship between the two, given that they are both single now, a source told People that Sandra, 47, and Ryan, 34, are “like brother and sister.”

The two were spotted at the Rendezvous Bistro in Jackson Hole on Sunday for what appeared to be a “really informal” dinner.

“They didn’t seem like they were a couple,” a source told the magazine. “It was very relaxed, totally friendly. She wasn’t romantic with anyone at the table.”