A US pastor and his wife whose two children were killed in a tragic car accident in 2015 have announced that they are now expecting twins.

In a Facebook post on Sunday, Hadley Eddings shared the couple's news.

"Y'all have held us up in prayer and we are so grateful!" She wrote. "Now we ask you to add two more Eddings to your prayers! We are expecting twins this summer!" 

The devout Christian couple made headlines when just days after the accident, they publicly forgave the truck driver who caused the incident in which Gentry Eddings' car was hit.

A worship leader at one of Charlotte's biggest churches, Forest Hills, Gentry was driving back from his sister's wedding on May 23 when his car was struck by 28-year-old Matthew Dean at traffic lights. His car then hit Hadley's, killing their two-year-old son Dobbs.

Hadley was eight months pregnant at the time. Their son, Reed, was born by emergency C-section, but also died three days later.

"We have, in our hearts, forgiven the man who did this. It was not the easiest thing to do, but in some ways it was because we know – Hadley and I – that Jesus Christ has forgiven us our debt... So in some ways, it was very easy to forgive a man who made an accident," Gentry said at their children's funeral.

He asked those present to also forgive Dean, and "anyone in your life who you hold anything against".

The couple later said they'd had to "learn how to do things differently", but still had faith in God.

Asked about how they cope with having survived the devastating incident, Hadley told WRAL: "The only thing I can think of is that if God left us here, he must just not be finished with us. That's the only thing I can think".