Gwyneth Paltrow thought she was "having a heart attack" when her father died.

Gwyneth Paltrow opens up about losing her dad 20 years on from his death

Gwyneth Paltrow opens up about losing her dad 20 years on from his death

The 49-year-old actress lost her father Bruce - who died following a battle with cancer at the age of 58 - back in 2002 and after returning from the funeral in the U.S, thought she was having a "heart attack" in her London home but couldn't call emergency services because she didn't know the telephone phone number.

She said: "I thought [the grief] was gonna split me open. I woke up in the middle of the night and I thought I was having a heart attack. The only reason I didn't call the emergency services is because I didn't know that in England you dial 999; in America it's 911. Honestly, I thought I was dying. It was really, really tough."

The Goop founder - who is mother to 17-year-old Apple and Moses, 16, with her ex-husband Chris Martin - went on to explain that she still doesn't know how she and her family made it through the "first year" of grief and that they just tried to "keep going" through the heartache.

Speaking on the 'By the Light of the Moon' podcast, she told host Holly Willoughby: "The first year was just beyond— I don't know how we all got through it, my mother, my brother and I. It was pretty messed up. Anyone will tell you, who loses a love of their life like that, there's just no other way but through. You just try to process your grief and keep going. One upside of having him die so young is that I had so much life left to build."