(AP/NEXSTAR) — The College Football Playoff announced Thursday it will expand to a 12-team event starting in 2024, completing an 18-month process that was fraught with delays and disagreements.

The announcement comes a day after the Rose Bowl agreed to amend its contract for the 2024 and 2025 seasons, which was the last hurdle CFP officials needed cleared to triple the size of what is now a four-team format.

The first round of the new playoff in 2024 will take place the week ending Saturday, Dec. 21.

Expansion is expected to produce about $450 million in additional gross revenue for the conferences and schools that participate.

The plan to expand the playoff was unveiled in June 2021, but the conference commissioners who manage the CFP could not come to the unanimous consensus needed to push the proposal forward. Expansion for the 2024 season was pronounced dead back in February.

But the university presidents and chancellors who oversee the CFP stepped in and revived the process over the summer. They approved the original plan for use by 2026, and threw it back to the commissioners, directing them to try to expand by 2024, if possible.

The College Football Playoff’s 12-year contract with ESPN runs through the 2025-26 season.

No longer haggling over the format, the commissioners needed to work through when and where the games would be played and whether bowl partners and championship games hosts cities could accommodate a change in schedule for 2024 and 2025.

The Rose Bowl issue was the last to be settled, as organizers for the 120-year-old bowl game were hoping to get some assurances from the CFP that they would keep their valuable New Year’s Day time when new contracts went into effect in 2026.

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CFP officials balked.

Facing the possibility of being painted as an obstructionist and potentially being shut out of the expanded playoff in the long-term, the Rose Bowl agreed to move forward on good faith.