Said a smitten Mr Dotcom: "I'm in love. We're in love. This is not some fling - this is serious."
Ms Donnelly is a third year business and law student at Auckland University of Technology.
She ended her previous relationship just over a week ago.
Dotcom told the Herald the relationship had taken off at "internet speed".
"I thought I would never love again. My heart turned ice cold after my separation from Mona. To love and be loved is what happiness is all about. I'm so happy that I met Liz and that I can feel those butterflies again," Dotcom said.
Mr Dotcom said his new partner was incredibly caring and the pair enjoyed spending hours together.
"Before anything she is kind and very considerate and sweet. It's just great to spend time with her."
While the couple were prepared for their detractors they were focused on their new-found happiness and live together as a regular couple.
"We want to go to restaurants and watch a movie without anything to hide," he said.
"We want to enjoy this. We want to be a normal couple.
"There will be all kinds of comments. Everyone will have an opinion. We'll take it as it comes."
Ms Donnelly revealed details of an unorthodox first date spent at the lavish penthouse with estranged wife Mona and the children.
"I came over here (to the penthouse). We just hung out inside and the kids were here and Mona was here but we got on well," she said.
She said her family and friends had been asked to initially keep the new relationship under wraps until the pair were certain where it was headed.
"All my friends know and are cool with it. My family are fine with it too," Ms Donnelly said.
The couple were now excited by the future.
"Everything is going so well," Mr Dotcom said.
"My luck has changed once I moved away from that mansion.
"This year is starting great. Happy kids. New love. Great legal team. MegaNet is coming together. Beautiful new home. And you, my friends! :)," he tweeted last month.
Dotcom has been on his own since his wife of five years, Mona, left him in March 2014.
Dotcom said he now planned to divorce her when the official two-year separation period ended.
He said it took a long time to get over his wife leaving and she would always be special to him.
"She has given me my amazing children and I'm very grateful for that," he said.
Mr Dotcom has made it no secret he was keen to have a new partner, even turning to Twitter to find love.
In December, a judge cleared the way for Dotcom to be extradited to the US to face internet piracy charges. His legal team is appealing the decision.
