United Kingdom, June 23 -- Hilarie Burton found it "really hard" to shoot her return to The Walking Dead universe.

The 42-year-old actress made a surprise return as Lucille in TWD: Dead City on 15 June, when Negan - who is played by her real-life husband Jeffrey Dean Morgan - hallucinated his dead spouse after suffering a head injury, and emotionally apologised for failing to keep his cancer-stricken wife alive.

And Hilarie has praised her husband's performance and genuine emotion in the scene, which was filmed just days after his father's death.

She told People magazine: "Please forgive me if I get upset. I just watched it. I didn't see it on Sunday. This was a really hard episode to shoot.

"What people didn't know is that, throughou...