Adele's estranged father wants to see her baby before he dies of cancer.
Mark Evans admitted he wasn't there for his daughter but has reached out in the hope he can meet his 10-month old grandson Angelo in case he passes away before he gets the chance.
He told The Sun on Sunday newspaper: "I was not there for my daughter when I should have been.
"I have regretted that every second of every day. It tears me up inside.
"I still haven't met Angelo and I'm facing the fact I may never do. It could be over for me before I get to make my peace with Adele."
Mark, 51, is an ex-alcoholic and knows he is to blame for their rift after he walked out on her mother Penny when Adele was three.
However he is still attempting to repair their relationship - although he compared contacting the star to attempting to "call the US president".
He said: "I'm hitting a brick wall. Trying to get hold of my daughter is like trying to call the US president.
"All my friends say, 'What's going on Mark?' I have to tell them I just don't know. I've just been ostracised.
"I haven't got Adele or Penny's number. I sent birthday cards via her record label but never hear back."
The part-time plumber had tumours removed from his stomach and colon after doctors discovered 11 potentially fatal growths, and he is awaiting tests to see if the disease has stopped spreading.
Mark insisted meeting his grandson and reconciling with Adele would be "the best tonic" and explained he wanted to enjoy Angelo growing up, just like he did with his daughter.
He added: "I remember taking Adele to the zoo in the holidays. I had a cut on my arm that had scabbed over. When she went to the loo, I scratched it so it would bleed.
"When she came out I told her a lion had jumped the fence and I had to wrestle it. that's the kind of thing I'd love to do for Angelo.
"I want to take him for walks in the park and eat ice cream together on Barry Island."