Emily Deschanel is expecting her first child with husband David Hornsby.

The 34-year-old 'Bones' star - who married writer-and-actor David in a small ceremony last September after dating him since 2007 - has confirmed she is due later this year but refused to give any more details.

However, Emily's younger sister - singer-and-actress Zooey Deschanel - couldn't contain her excitement at the news that she is to become an aunt and quickly took to twitter to share the news.

She wrote: "My big sister, Emily (aka bones) Deschanel and her husby, David Hornsby, are going to have a baby! I am super excited to be an aunt! (sic)"

'Bones' creator Hart Hanson later tweeted: "I have passed on to Emily the wave of love and support you've manifested since her pregnancy announcement. She is touched and grateful!"

Emily is best known for her role as forensic anthropologist Dr. Temperance Brennan opposite David Boreanaz as Special Agent Seeley Booth in the TV series 'Bones' while David plays former priest Matthew Mara (also known as 'Rickety Cricket') on 'It's Always Sunny in Philadelphia'. He is also a co-executive producer of the show.

Zooey, 31, married Ben Gibbard, the lead vocalist for The Postal Service and Death Cab For Cutie, in 2009 in a private ceremony near Seattle, Washington.