Since beating Jeff Horn in 2018 to become WBO welterweight champion, fans have been crying out for the two American welterweights to face off in the ring.
Four years onwards and we are now closer than ever to witnessing the two rivals square off - and if it does happen then all four world titles will be on the line.
Spence beat Yordenis Ugas in April to add the WBA belt to his IBF and WBC titles and is the unified champion at 147lbs.
With 'Bud' now being a promotional free agent, it leaves the 34-year-old free to work with Al Haymon and PBC, something Crawford's former promoter Bob Arum refused to do.
Yet despite the apparent bad blood between the champions, Crawford remained respectful when speaking about the WBA, WBC, and IBF world champion.
"I'm excited about it. I can't wait until the contracts get signed and I get into training camp and picture myself walking down that aisle to put on a great show. I've been waiting for this moment all my life, it's right there.
"I always gave Errol respect. I never tried to down talk his talent or his skills in any way, shape, form, or fashion.
"I grew up as a boxing fan, when Errol was in the Olympics fighting for the USA team, I was rooting for him. When he started his professional career, I was rooting him on."
A contest between the two welterweights has always been fiercely debated between fans.
Some favour Crawford's boxing IQ and counterwork whereas others believe Spence's pressure to be too much and overwhelm 'Bud'.
Despite this, Crawford played down his potential opponent's skills within the ring and is predicting an 'exciting fight'.
"I feel like I can stay in the pocket, I can be first, I can be first and last, I can counter, I can switch, I can do most things in the ring.
"A lot of people say I start slow but finish strong. It's gonna make for an exciting fight.
"Whatever he brings to the table we are going to be 120% prepared for, his onslaught with the pressure, we're gonna be ready."
While Spence is on top of Crawford's agenda, the three-time world champion is still looking to the future and has picked undisputed champion Jermell Charlo as a potential opponent.
Charlo - who is stablemates with Spence - is plotting a move up to 160lbs but may remain at junior middleweight for a couple of more fights, and Crawford could be in line.
"I'm 100% confident, this year. Like I said once I beat Spence, if Charlo don't move up then I'm coming for him.
"I've got two people on my hitlist, Spence first and then Jermell," added Crawford.