Whew ... have MERCY, "GMA."
The ABC morning show, which airs between 7 and 9 a.m., on Wednesday hosted a "Full House" mini-reunion that featured none other than former cast members Bob Saget (Danny Tanner), Dave Coulier (Joey Gladstone) and hunky John Stamos -- who proceeded to unbutton his dress pants.
Check out 5 highlights from the "Full House" mini-reunion on "GMA."
1. Stamos strips down
The actor revealed his Calvin Klein underwear, adorned with pictures of Oikos Greek yogurt containers.
"Good Morning America" had just aired a clip from the trio's ad for the brand that is set to air during the NFL Super Bowl XLVIII on Super Bowl Sunday, Feb. 2. It shows Stamos wearing a shirt and boxers. Saget, who played his character Uncle Jesse's brother-in-law and compulsively-cleaning dad Danny Tanner, asks him to remove his pants as he and Coulier, who played their roommate Joey, scrub a kitchen.
"Eight years, they've been trying to take my pants off," Stamos, who is a spokesmodel for Oikos, joked on "GMA."
Coulier also showcases his own underwear in the ad. A teaser for the commercial, released last week, also shows him wearing a red onesie.
The popular sitcom "Full House" aired between 1987 and 1995 and also starred Candace Cameron Bure, Jodie Sweetin and Mary-Kate and Ashley Olsen as Tanner's daughters DJ, Stephanie and little Michelle. The show still airs in reruns today.
"I mean, we're on our third generation of 'Full House' fans," Stamos said. "Every four years, there's a new 'Full House' fan born."
2. John Stamos calls Bob Saget and Dave Coulier his "brothers."
Stamos said he had suggested to representatives of Dannon, which manufactures Oikos, to bring his "brothers on for the Super Bowl."
Coulier revealed the trio recently hung out.
"These two visited me at my house last week and we sat in my backyard by the little fire pit and we joked around," he said.
"And he wore the onesie from the commercial," Saget said.
"I love that onesie," Coulier replied. "That thing is so comfortable."
The cast of "Full House" has gotten together for reunions before. In September 2012, the three actors hung out with Bure, Jodie, Lori Loughlin, who played Jesse's wife Becky, and Andrea Barber, who played DJ's mischievous BFF Kimmy Gibbler.
3. John Stamos reveals origin of "Have Mercy" line.
"You know, Gary Marshall, [creator of shows] "Happy Days" and "Laverne & Shirley" said, 'Come up with a catchphrase,' Stamos said on "GMA." "So I said, 'Have Mercy' from 'Pretty Woman' by Roy Orbison."
Orbison's 1964 song "Oh, Pretty Woman" contains the lyric, "Mercy."
4. "Full House Fumble"
The trio played a Super Bowl-themed game in which they were asked "Full House" trivia questions. Coulier and Saget both answered two correctly and Stamos got one right.
Among the correct replies -- Coulier stated the title of the song the three sang to Michelle was "Teddy Bear," Saget remembered that one of Tanner's daughters totaled his beloved car, Bullet and Stamos named the song Danny wanted to sing at DJ's school ("My Generation" by The Who, backed by Jesse and his band).
5. No one knew how to tell the Olsen twins apart.
The correct answer? Mary-Kate has a freckle above her lip. (Also, Ashley is an inch shorter.)
Watch the "Full House" mini-reunion in the new Dannon - Oikos Super Bowl ad below - includes a teaser and the entire commercial.