Ellis has been playing for England Under-20 in Argentina
The Dragons have recruited Wales-qualified Arthur Ellis, the Wasps and England Under-20 hooker following his brother Hugo from London to Newport.
"I wanted to sort things out before the IRB Junior World Championships [in Argentina] so I could focus properly on things here," said 20-year-old Ellis.
"I signed for Newport Gwent Dragons just before I came out, which I'm really excited about."
Danny Wilson has also joined the Dragons, as an assistant coach.
The former Wales national skills coach arrives from London Welsh, having also coached with the Blues, Cardiff RFC, Wales Sevens and at Wales age-group levels.
This is an exciting time to be part of the team at Rodney Parade
New Dragons assistant coach Danny Wilson
"Joining the Dragons presents a great opportunity for me as a coach," said Wilson.
"They are a side who are constantly developing as their success last season shows.
"This is an exciting time to be part of the team at Rodney Parade and I hope to contribute to further success in the coming campaign."
Back-rower Hugo Ellis' signing was announced by the Dragons on Monday, the 22-year-old former England U20 captain stating his intention to pursue Wales ambitions.
The Ellis' father, Wyn, is Welsh and played for Neath and Wales Schools.
Arthur Ellis played for Wales U16s before representing England at U18, 19 and 20 level.