He graduated to their first-grade squad for the 2013 season following some impressive performances with the club's Under-20s.
Standing 183 cm (6ft) and weighing 91 kg (14st 5lbs) Solomona has played full-back, wing and centre. He was released from his contract with Melbourne to join the Broncos for 2014.
London Broncos head coach Tony Rea said: "Denny is a talented individual who has been really brave in his decision to come here. He's been sitting behind Billy Slater as his understudy at Melbourne but has taken a decision to come here. This is a way of putting himself out on his own stage.
"He had a contract at Melbourne, which he left to join us, and had the full support of Melbourne and the Broncos to do that."