Dwayne Johnson has gushed about his daughter Jasmine on her second birthday.

The 45-year-old actor has taken to social media to pay tribute to his youngest child - who he has with his partner Lauren Hashian, who he is also expecting his third child with - and in the sweet post Dwayne promised his ''lil' piece of sugar'' he will ''always love, protect and guide'' her for the ''rest of [his] life''.

Dwayne - who also has 16-year-old daughter Simone with his ex-wife Dany Garcia - has shared a photograph of Jasmine reaching out for her birthday cake on his Instagram account.

The 'Moana' star captioned the post: ''The Big 2.

Happy Birthday to our lil' piece of sugar Jasmine Lia.

''Just like your big sister Simone and your baby sis on the way... as your daddy, you have my word I'll always love, protect and guide you the rest of my life. (sic).''

And Dwayne is excited to celebrate the youngster's birthday because he has had a busy year so far and is eager to get home and relax with his family during his time off.

He continued: ''Timing was perfect as I've worked all year with no time off until now and bringing my ohana home to Florida was just the anchor I needed for the holidays. (sic).''

Although Dwayne - who is also known as The Rock, which is a moniker he acquired when he was a professional wrestler - has promised to protect his brood for the rest of his life, he has asked for one small thing in return, which is ''one hour of 'special alone time''' with any future boyfriend when she is older.

He quipped: ''Just promise me I get one hour of ''special alone time'' with any boy you decide to bring home in the far FAR future.

And thank you to everyone for all the birthday love and wishes you sent our way. #Ohana #BirthdayGirl (sic).''