Ben Affleck insists he and Jennifer Garner are still "good friends".

Ben Affleck

Ben Affleck

The 'Batman v Superman: Dawn of Justice' actor split from the 43-year-old actress last June after 10 years of marriage but they are "doing their best" to get on well for the sake of their three children, Violet, 10, Seraphina, seven, and four-year-old Samuel.

He said: "You know, we're good friends and we're doing our best and our kids are fabulous and we're working our best for them."

Meanwhile, the 43-year-old star joked he thinks his son will end up in "therapy" because the youngster is so convinced his new movie is real and that co-star Henry Cavill really is Superman.

He quipped to talk show host Ellen DeGeneres: "I haven't done anything that my kids can see for a long time, so I thought that would be kind of cool. My son thinks it's really cool.

"He came to the set, he saw me, he was a little bit suspicious. He was like, 'Is that the real Superman?'

"He's four so to him that's the real Superman.

"When I leave, he's like, 'Dad are you going to the Batcave?' So I'm like, 'Yes, I am.' And I know eventually he's going to be in therapy, like, 'He lied to me, there's no Batcave, he's doing Ellen!' "