The friendship blossomed in 2009, at President Barack Obama's inauguration.
It's a relationship that's been partly out of their hands since Obama and Bush are often seatmates at official functions. Of which, they attend a lot.
But even when they aren't seated, the couples can be seen together.
In 2016, Obama and Bush showed the world their enduring friendship with a sweet embrace.
The two attended the dedication ceremony for the National Museum of African American History and Culture.
Jenna Bush Hager, Bush's daughter, called it "the hug that went around the world."
next slide will load in 15 secondsSkip AdSkip AdIn 2016, the pair shared a moment during a memorial service for five police officers who were killed in Dallas.
"Party doesn't separate us. Color, gender — those kinds of things don't separate us. It's the messages that we send," Obama told NBC News.
Bush spoke to People about their friendship in 2017.
"I needle her a little bit and around her, I'm fairly lighthearted," he said. "[The Obamas] are around serious people all the time and we just took to each other."
In 2017, he told Ellen DeGeneres that their friendship surprised everybody.
"That's what's so weird about society today, [the surprise] that people on opposite sides of the political spectrum can actually like each other," he said.
In 2018, at late Sen. John McCain's memorial, Obama saw Laura Bush hand her husband a cough drop, and asked for one, too.
"I looked over and I said, 'Hand me a cough drop," she told "Today." Bush did as he was told.
next slide will load in 15 secondsSkip AdSkip AdA clip of Obama mouthing "thank you" after the handover went viral.
In 2018, Obama said Bush was her "partner in crime."
In an interview with Today, Obama spoke about their friendship, after their interaction at the memorial had gone viral.
She said she loved him "to death," and that he was "a wonderful and funny man."
Then, at Bush's father's memorial in late 2018, as he greeted a line of past and present American presidents, he slyly slipped another cough drop into Obama's hand.
In December 2019, Obama defended Ellen DeGeneres when the host was ridiculed for having a friendship with Bush.
DeGeneres was criticized for her friendship with Bush after a photo went viral showing the pair sitting together at a football game.
next slide will load in 15 secondsSkip AdSkip AdObama told "Today" that while they agreed on policy, their values were the same.
"We don't disagree on humanity. We don't disagree about love and compassion. I think that's true for all of us. It's just that we get lost in our fear of what's different," she said.