Sarr, a transfer from Wake Forest, was arguably the nation's best transfer last spring, and Toppin, a transfer from Rhode Island, is the younger brother of former Dayton star and projected lottery pick Obi Toppin.
"I'm excited for Olivier and Jacob," Kentucky coach John Calipari said. "Both have worked really hard and deserve this opportunity. They were both hopping and skipping out of my office after getting the news because they've been waiting on this day. I want to thank the NCAA and the SEC for considering the unique circumstances surrounding this season, and we appreciate them working with us throughout this process.
"In Olivier's case, I know this has been difficult for him, everything from the coaching change at Wake Forest to deciding his future to waiting through this process. He's gone about his business every day and continued to work hard in hopes of joining his teammates on the floor this winter. Jacob came here needing a fresh start. From day one, he's been a great teammate and been an important part of this group in practice. He has tremendous upside and a great spirit about him. I know we're all looking forward to chasing our goals soon."
Sarr, a 7-footer from France, averaged 13.7 points and 9.0 rebounds for Wake Forest last season, earning third-team All-ACC honors. He was at his best late in the season, scoring 25 points in a win over Duke and following that with 30 points and 17 rebounds against Notre Dame.
"I want to start by thanking the NCAA, the SEC and Kentucky for this opportunity," Sarr said. "I am excited to finish my college career in front of the Big Blue Nation and chase No. 9 with my team."
Sarr was referring to Kentucky's eight NCAA national championships and the quest for a ninth this season.
Toppin, a 6-foot-8 forward, averaged 5.1 points and 3.9 rebounds in a reserve role at Rhode Island last season. He started four games for the Rams.
"This is a big day for me, and I want to thank the NCAA and my Kentucky family for their help in this process," Toppin said. "I can't wait to get on the court with this group of guys and play in front of our fans."
Kentucky lost eight of its top nine players from last season, with six players leaving for the NBA draft, Johnny Juzang transferring to UCLA and Nate Sestina playing his final year after graduating and transferring from Bucknell. Keion Brooks is the lone returnee for the Wildcats, but they're bringing in the nation's No. 1 recruiting class, led by five-star guards B.J. Boston, Terrence Clarke and Devin Askew.
With Sarr and Toppin officially in the fold, Kentucky will likely move into the top five of ESPN's preseason rankings. The Wildcats were No. 12 in August's update.