"This is for the fans, thank you for the support," Pearson said on Twitter.
Pearson and Guillard will fight in the UFC Fight Night 29 co-main event. Middleweight contenders Michael Bisping and Mark Munoz square off in the main event. UFC has yet to announce additional bouts for the card.
Guillard was on the fast track toward a 155-pound title shot two years ago, but a first-round submission loss to Joe Lauzon in October 2011 halted his charge. He would win just one of his next four fights.
In his most recent outing, on July 27, Guillard looked impressive en route to a second-round knockout of Mac Danzig.
The 30-year-old Guillard has a professional record of 31-12-2 with one no contest.
Pearson, 28 and a native of Sunderland, England, has won two fights in a row, each by TKO. He registered a second-round knockout of Ryan Couture in his most recent fight on April 6. The win improved Pearson's record to 15-6.
Bisping and Munoz rebounded from knockout losses with impressive victories in their most recent bouts. Bisping defeated Alan Belcher by unanimous decision on April 27. Munoz overwhelmed Tim Boetsch on July 6 en route to a unanimous decision.
ESPN.com ranks Bisping fourth among middleweights; Munoz sits at No. 8. Fighting for the first time in his native England since October 2010, the 34-year-old Bisping will carry a pro record of 24-5 into the cage.
Bisping has never lost a professional mixed martial arts fight in England, where he is 16-0.
Munoz, 35, is 13-3. He has won five of his last six fights, the only loss, a second-round knockout, coming against middleweight champion Chris Weidman in July 2012.