Katharine McPheeandDavid Fosterhave tunnel vision when it comes to their relationship. Their focus is on one another.

That connection was on full display duringCelebrity Fight Nightin Italy on Sunday, where McPhee performed “I Can’t Help Falling In Love with You” withAndrea Bocelliand barely took her eyes off of Foster, who accompanied on piano.

“A few years ago I told you she was the one,” Bocelli told Foster just before the duet, to which he responded, “You were right.”

The luxurious weekend-long charity event, which raises funds for theBarrow Neurological Institute and the Muhammad Ali Parkinson Center, nearly doubled as an engagement celebration for the pair. Afterdodging relationship rumorsfor months, they confirmed in July thatFoster had proposedwith a sparklingemerald-cut diamond ringwhile they vacationed in Anacapri, Italy.

David Foster and Katharine McPhee.

2018 Celebrity Fight Night Italy, Porto Venere, Italy - 06 Sep 2018

Opening up for the first time in this week’s issue, the hit-making musician, 68, and formerSmashstar, 34, tell PEOPLE that despite their 34-year age difference (which has spurred a number oflighthearted jokesbetween McPhee and his daughtersSara, 37, and Erin, 35) they’re much more focused on all that they have in common.

“We genuinely love and respect each other and have for a very long time,” says McPhee. The pair first met in 2006 whenFoster mentored herand other contestants onSeason 5 ofAmerican Idol.

“She didn’t catch my eye on the first day because I was so busy trying to do my job,” says Foster, who went on to produce McPhee’s first single. “But,” he adds, “the reality is that in the last 12 years I’ve always had a connection with her.”

Katharine McPhee and David Foster.Jason Merritt/Radarpics/Shutterstock

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As for what bonds them, “the fact that we are both in the music industry helps,” says Foster, who recently embarked on hisThe Hitman Tour. McPhee recently wrapped her run inBroadway’sWaitress. “We understand each other,” he says.

RELATED VIDEO: David Foster Talks Katharine McPhee’s “Waitress” Debut: “She’s the New Belle of Broadway”

And while they knowtheir significant age gaphas been a hot topic, they’re tuning out the noise. “It doesn’t make sense to a lot of people, but it does to us,” McPhee says of their love.

And they’ve got thefull support of his daughters, who have funmaking jokes, but both“love” McPhee, a source previously told PEOPLE.

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Now in the midst of planning what will be Foster’s fifth marriage (hedivorced Yolanda Hadidin 2017) and McPhee’s second (shedivorced Nick Cokasin 2016), the couple is banking on forever.

“He has things to learn from me and I have a lot of things to learn from him,” says McPhee, “so I think we have a nice yin and yang.”

For more on David Foster and Katharine McPhee’s Romance, pick up this week’s issue of PEOPLE, on newsstands Friday.

source: people.com