Lemuelu has signed on a two-year deal which will see him in the Dolphins squad for 2023 and 2024.
He is yet to make it onto the field in 2022, spending one game on the interchange bench for a total of zero minutes against the Canberra Raiders during Round 6, but managed 13 games last year.
The centre, who made an off-season transition to the back row, will provide Wayne Bennett's side with solid depth in two positions on what is believed to be a cut-priced deal.
The 23-year-old, who was born in New Zealand, has scored two NRL tries in his 20 top grade games.
Dolphins' CEO Terry Reader said Lemuelu is an exciting prospect in an official club statement.
“Connelly is an exciting prospect in his new position and we are keen to see what he can bring to the Dolphins,” said Reader.
“Once again, this continues our efforts to build a squad for the future and we are excited about the type of player Connelly can turn into in the NRL.”
Lemuelu joins Tom Gilbert as another young Cowboy heading south and adds to an experienced forward pack - featuring Jesse Bromwich, Kenneath Bromwich, Felise Kaufusi and Mark Nicholls - with some much-needed youth, while he could also yet line up in the centres - where the Dolphins are yet to make a signing with NRL experience, although Valynce Te Whare joins the top 30 next year in that position.