Liam Hemsworth supported his future wife Miley Cyrus by surprising patients at a children's hospital in San Diego.

The 24-year-old singer and her actor fiancé, 26, were guests at the Rady Children's Hospital in San Diego on Thursday (29.12.16) as part of Miley's Happy Hippie charity which aims to fight injustices facing homeless youth, LGBTQ youth and other vulnerable populations.

In a series of photos posted to her Instagram account, the 'Wrecking Ball' hitmaker wrote: ''It's a VERY special day for @happyhippiefdn !!!! Will fill y'all in SOOOOON! Can't wait to share

''Thank you @radychildrens for your incredible dedication to bettering the lives and health of the beautiful youngins @liamhemsworth and I got to visit today!

''Thank you for having us today! Beautiful children everywhere! @liamhemsworth is OFFICIALLY a #happyhippie !!!! @happyhippiefdn

''Queen Warrior!!!! Yes you are!!!!! (sic)''

And it wasn't just Miley who shared her excitement on social media, as the Facebook page for the hospital also posted a message thanking the pair for their time.

The post read: ''Today we received a surprise special visit from a couple of people you might recognize! Thank you to Miley Cyrus, Liam Hemsworth and The Happy Hippie Foundation for bringing joy and laughter to our patients! (sic)''

Miley - who describes herself as ''pansexual'' - established her Happy Hippie Foundation to help homeless and LGBT (Lesbian, Gay, Bisexual and Transgender) youth last year because she can relate ''so much'' to the youngsters' problems, even though she has no sexual confusion herself, but because she believes people are ''constantly transitioning''.

Asked why she started the foundation, she explained: ''I relate so much to it. It's very strange, because I'm not sexually confused in any way. I'm very much--the word is pansexual. That just means everyone.

''It doesn't stop at girl, boy, or if someone's in a transition. I don't see people ever for who they were before who they are right now.

''I think of who I was before who I am right now; that's a transition in itself. Everyone is constantly transitioning. When there's a thing you have to do, you have to do it. That's how I got with ['Saturday Night Live']; every time I was like, Why am I here? I'm so scared. You're about to be live!''