The 41-year-old presenter unveiled her stunning yellow sapphire ring on 'The View' today (16.04.14), and revealed her 11-year-old son Evan - who she has with former spouse John Mallory Asher - helped the New Kids on the Block singer with his proposal last weekend.
After hiding her hand behind the show's desk, Jenny showed off the ring and exclaimed: ''I just got engaged!''
She then wept as she recalled the proposal and explained Donnie, 44, had got down on one knee to pop the question.
She said: ''This weekend I was sitting with Donnie ... and he went into the other room and Evan out came with a card that said 'Will' and he handed it to me.
''Then Evan ran away and came in with a card that said 'You.' I started crying and then Evan came into the room with the word 'Marry' - but spelled wrong.
''Last Donnie came out with Evan and Donnie's shirt said 'Me' and he got down on his knee ... Of course, I said 'Yes.' In that moment Evan yelled, 'I have another dad!' and it made all of us cry and I feel like the luckiest girl in the world and he's so wonderful.''
The couple - who started dating last summer - are unsure when they will marry.
Jenny admitted: ''We don't know yet.''
She said they were considering August, but her co-host Barbara Walters said they could tie the knot in her New York home if they marry in September.
However, she added: ''On the wedding night, you cannot stay in my apartment.''
Jenny previously admitted Donnie had made her reconsider her views on marrying again.
She has said: ''I've said on every interview that I was like, 'Never get married again ever,' and, of course, you never say never. I think he would be an amazing husband, so if he does, I would for sure say yes. I wouldn't be surprised if I was the one proposing.''
Donnie has two sons from his nine-year marriage to Kim Fey, which ended in 2008.
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