TCU trustees will meet on Monday and then are expected to accept the Big 12's invitation to join the conference, sources confirmed Sunday.
In a statement Monday, the school said it will make a "major announcement" at 7 p.m. ET at the Kelly Center on campus.
A move to the Big 12 allows TCU to rekindle some of the rivalries it had for so long in the Southwest Conference, which disbanded in 1996.
TCU, the defending Rose Bowl champion, agreed earlier this year to leave the Mountain West Conference for the Big East, which has an automatic BCS berth.
A source told ESPNDallas.com last week that TCU would have to pay a $5 million exit fee to leave the Big East, but would be able to join the Big 12 in time for the 2012-13 athletic year.
If Missouri stays in the Big 12, the league would have 10 teams with TCU taking the place of Texas A&M, who is headed to the SEC next year. Missouri is exploring its options.
A Big 12 source told ESPN.com last week that the conference got more "expert information about fit/value/enhancement to our league," late Wednesday. The Big 12 knew of TCU's keen interest.
"There wasn't any reason to wait if we knew it would be the right choice," said the source, who added that "additional expansion is still possible."
TCU is undergoing a $143 million renovation to Amon G. Carter Stadium, which will have more suites, a new press box and close to 50,000 seats when completed. The school expects it to be ready in time for the 2012 opener.
A move to the Big 12 would also be a financial windfall for TCU.
Big 12 chancellors and presidents agreed last week that schools would equally share revenue from the conference's television deals as long as member universities give the league those top-tier rights for at least six years. The agreement is subject to approval by the schools' governing boards.
The revenue-sharing plan would give each school about $20 million in June and that figure is expected to grow by 2013 when the league's new 13-year contract with Fox Sports kicks in. The Big 12's contract with ABC/ESPN expires in 2016 and likely will bring in additional money when renegotiated.
Information from senior writer Andy Katz, who covers men's college basketball for ESPN.com, and The Associated Press, was used in this report.