Kelly Rutherford says Gossip Girl costar Blake Lively will be a great mom! Credit: James Devaney/WireImage

Lily van der Woodsen approves! Blake Lively's Gossip Girl costar and on-screen mom Kelly Rutherford told Us Weekly she thinks Lively will be a "great mom!"

"I"m so happy for her," Rutherford said at an AFLAC yoga event in New York City on Thursday, Oct. 9. "She was always so sweet to my kids on the [Gossip Girl] set. I was a new mom when we were on Gossip Girl together, and she was always so loving towards my kids so I think she’ll be such a great mom," the actress added of Lively, who played her daughter Serena van der Woodsen on the hit CW show. 

"She’s just beautiful," Rutherford went on to gush about the expecting star. "And she has an amazing family, so I think she understands the beauty of family, and the balance of it [all]," she added.

Lively, 27, announced she's expecting her first child with Ryan Reynolds on her website on Oct. 6. The mom-to-be posted several pictures of pregnant women, celebrating in particular "that special moment at the creation of family," and ended the post with a stunning surprise photo of her own pregnant belly.

The blonde actress has been vocal about wanting kids since tying the knot with Reynolds in September 2012. "I gotta get started," she told Marie Claire earlier this year. "If I could spit out a litter of kids, I would."