Hilary Duff gushed over her sister Haylie Duff's engagement news to boyfriend Matt Rosenberg with a sweet message -- see a photo Credit: Courtesy Hilary Duff; Inset: John Sciulli/Getty Images

A new brother-in-law! Hilary Duff couldn't be happier for big sister Haylie. The actress sent Haylie a sweet message just hours after the food blogger announced her engagement to boyfriend Matt Rosenberg via Twitter on Thursday, April 4.

"Love you guys so much!!!! @mr_sts @haylieduff," Duff, 26, wrote. Alongside the caption, the star shared a sweet snapshot of Haylie, 29, and her beau snuggling up to each other on the couch.

As previously reported, Duff and Rosenberg got engaged on April Fools' Day earlier this week. She opened up about the special moment on her Real Girl's Kitchen blog and showed off her gorgeous brilliant cut diamond ring via Instagram.

"This week has seriously just become the best week of my life!" she wrote on April 3. "Matt just took me by total surprise and proposed…on April Fools' Day of all days! The moment was genuine and sweet (like him!) and I couldn't wait to say yes!"

"We are so excited and happy to share our wonderful news with everyone!" she added. "We both feel so blessed to have the love and support of our family and friends and can't wait to start this new adventure!"

So, will newly-single Hilary be the maid of honor? That's yet to be revealed, but seems likely. Back in August 2010, Haylie took on the role in Hilary's wedding to former NHL player Mike Comrie. The pair split in January, and share son Luca, 24 months.

Real Girl's Kitchen premieres on Ora.tv Wednesday, April 9.