'When I look at her...I find it so hard because it's quite personal actually,' a very tearful Delta said in the trailer.
Melissa Doyle, Sunday Night's host, also hinted that the 69-year-old Grease star - who has been receiving treatment for cancer - will be making an 'announcement' regarding her health.
Channel Seven
'The interview Olivia Newton-John knew she had to do,' Melissa said in a voiceover, adding that the the star 'wants to put the record straight while she can'.
'I wasn't sure, you know, if I'd make it,' Olivia added, in a snippet from the interview.
Melissa concluded the sneak peek by saying, 'Olivia's very personal announcement, in her own words.'
Sunday Night airs on Channel Seven at 8pm.
