Billy Ray Cyrus is set to become a grandfather.

The 'Achy Breaky Heart' singer's son Trace Cyrus is thought to be expecting his first child with former The Suite Life of Zack and Cody star Brenda Song, according to reports released on Billy's 50th birthday yesterday (25.08.11).

However, Trace - who used to date Demi Lovato - and Brenda are yet to confirm the speculation that they're expecting a child.

It would be the first child for the 23-year-old beauty and the 22-year-old Metro Station rocker, who recently encouraged his fans on twitter to celebrate his dad's birthday.

He tweeted: "Happy birthday to my dad! check out his new single 'Nineteen'.

Billy - whose daughter is pop star Miley Cyrus - is also set to release a new album, entitled 'The Boot', which features a number of patriotic songs.

And he has recently described the record as a "tribute to veterans and the men and women who are sacrificing so much for our freedom and the sacrifice their entire family is making."