Foster, a five-star inside linebacker, announced his decision in the cafeteria of his high school. Foster previously starred at Troup County High in LaGrange, Ga., before his head coach was fired at the end of the school year. In August, he crossed both state and enemy lines by transferring to Auburn High School, a stone's throw from the Auburn University campus.
Foster committed to the Crimson Tide last July and maintained he was 100 percent with Alabama -- until now. In front of a room with plenty of Auburn supporters, Foster held up his daughter, A'Ziya, and unzipped her sweatsuit to reveal an Auburn Tigers cheerleading uniform underneath. He then put an Auburn hat on, posed for photos and made his verbal commitment official.
"Over the last few weeks, I've really put a lot of thought and time into where I want to continue my football career," Foster said in a statement. "I am blessed that I have the situation that I am in. I have such a great opportunity.
"I want to make an announcement so I can get this behind me and get on with the work that I need to do for high school and getting prepared for college both academically and athletically. I am going to roll to Auburn University."
The announcement was met with a round of applause from the family, friends and fans in attendance.
"I have a lot of respect for the Alabama people -- the coaches and all of the other people and the fans," Foster said once the crowd quieted. "But at the end of the day, I feel like Auburn University is the place for me and my family. It has the best situation for me and my family.
"I am 100 percent confident with my final decision."
Foster thanked everyone in attendance, hugged his family and made his way out, choosing not to comment further on his decision.
Foster's coach, Tim Carter, said he was in the dark about the decision until receiving a phone call late Wednesday night from Foster, who asked Carter to set up the format for Foster to make his announcement.
"His recruitment has really heated up of late," Carter said prior to the announcement. "I've seen a lot of guys shut it down after committing. Reuben continued to take his visits."
Carter said he hoped his decision to attend Auburn would put the hectic recruiting process behind him.
"He has a lot of great choices," Carter said. "He's ready to get this behind him."
Auburn has secured three of the top 10 prospects in the ESPN 150, and all three play on defense. Foster, the top-ranked linebacker, joins No. 5 Carl Lawson, the nation's second-ranked defensive end, and No. 8 Dee Liner, the top defensive tackle.
The Tigers' recruiting class was ranked No. 12 nationally before Foster decided to switch.