"Loving my time with the ITV gang in Oz. Really great people," Keith (38) wrote. "But gotta say I must be getting old because I'm missing my clan so much."
Keith headed to Oz last week and seemed to be having the time of his life, lounging by the pool and enjoying the sun.
"Lying by the pool chilling with the gang. It's a dirty job but someone's got to do it!" he wrote on Twitter.
The Boyzone man has been hanging out with his pals Ronan Keating and Brian McFadden in Sydney, and also been spending time with Bray native Laura Whitmore.
But despite the TV appearances and glorious summer days, Keith is pining for his kids, Jay (16) and Mia (12) as well as missus, Lisa.
The singer and actor has been married to Lisa for 14 years and says the secret to their happy marriage is keeping their private life private. He said: "We keep our problems behind closed doors."
Keith's son Jay has just starred in Corcadorca's critically acclaimed production of Romeo And Juliet after a susseccful stint in UK soap Hollyoaks.
Despite spending years on stage, Keith said he suffered from first night nerves when watching Jay take to the stage.
"I was very anxious and nervous before he got on stage. I was almost wishing I'd brought a pillow from back home so I could hide behind it!"