The actress and her professional partner broke their two-week tie for first place with singer Brandy Norwood and her partner Maksim Chmerkovskiy during Monday night's ninth eleventh-season performance show.
Grey and Hough finished in first place on the judges' leaderboard after they received 30 out of 30 possible points for their Latin cha cha and another perfect score of 30 for their ballroom waltz -- representing the season's first perfect 60 score.
"That's 30 out of 30 which gives you a perfect score for the night -- 60 out of 60 -- I'm glad to see the happiness coming back. How does that feel both of you?" Dancing with the Stars co-host Brooke Burke asked the couple.
"Wow!" Hough said.
"Spectacular!" Grey added.
"Wow it's just amazing, what a great night!" Hough exclaimed.
Disney Channel star Kyle Massey and Lacey Schwimmer finished in second place on the judges' leaderboard with 58 points after they received 29 points for their samba during the Latin round and an additional 29 points for their Argentine tango routine during the ballroom round.
They were followed by Norwood and Chmerkovskiy, who received 27 points for their paso doble and a perfect score of 30 points for their Argentine tango -- giving them a total of 57 points.
Teen mom Bristol Palin and partner Mark Ballas finished in fourth place with 53 points after their paso doble performance earned 27 points from the judges -- their highest score of the season -- and they received 26 additional points for their waltz.
The judges' scoring and home viewer votes that were cast after Monday night's performances will now be combined and one of the four celebrity and professional pairings will be eliminated on Dancing with the Stars' ninth eleventh-season results show tonight at 8PM ET/PT.