One Tree Hill star Danneel Harris Ackles expecting twins with Supernatural actor Jensen Ackles

American TV stars Danneel Harris Ackles and her husband Jensen Ackles have announced that they're expecting twins!

Danneel, who starred in hit show One Tree Hill, and Jensen, made famous for his role in TV series Supernatural, revealed that they'll soon be a family of five in sweet Instagram posts.

Soon-to-be dad of three Jensen, who was the first to announce the happy news, even revealed the gender of the twins, telling fans that a boy and a girl are on the way!

The actor took to Instagram to post a picture of two adult-size boots and a child's set - next to two new little pairs with a hint of blue and pink! He captioned the photo: 'Adding a couple of pairs of boots to the family later this year. #crazytimesahead'

Danneel, 37, shared the same sweet snap to her own Instagram account, alongside the caption: 'Yep! Doublemint here we come!'

The new arrivals will be brother and sister to their three-year-old daughter, Justice Jay Ackles, who the couple welcomed on 30th May 2013.

Fans have been quick to congratulate the pair, taking to Instagram to send well wishes. One user wrote: 'Congratulations to you both!!!! So happy for you! Gonna be the most adorable twins on this earth!' while another added: 'I can't stop dancing and crying- this is AMAZING!!! Congratulations to you and Daneel- happy days ahead !'

Danneel and Jensen are both famous for appearing in separate TV shows in the States. Danneel rose to fame in her role as Rachel Gatina in One Tree Hill, while husband Jensen, 38, currently stars as Dean Winchester in Supernatural, which he's appeared in since 2005.

The couple reportedly met while working on their 2007 movie Ten Inch Hero. Jensen popped the question in November 2009, and the pair married in Dallas a year later, on 15th May 2010.

Congratulations!