Grey's Anatomy has announced some changes to its main cast – with four of season nine’s interns becoming full members.

Camilla Luddington, Gaius Charles, Jerrika Hinton and Tessa Ferrer have been upgraded to series regulars for the upcoming tenth season.

The four actors currently play interns in the long-running drama, with Luddington starring as Jo, who is the love interest of Justin Chambers’ Alex.

The fifth intern, played by Tina Majorino, has so far not been upgraded to a regular. She recently signed up to reprise her role as Mac in the Veronica Mars movie, while she has also joined TNT's Legends as a series regular.

It is currently unconfirmed if Majorino will return to Grey's Anatomy in a recurring role.

Season nine of Greys Anatomy continues on Tuesdays on RTÉ Two.