U2 frontman Bono arrived with wife Ali Hewson -- the couple are long-term friends of Guggi.
Bono said that his pal often invites him for a sneak preview, but this was his first time to see the works of art.
"Normally I get to enjoy a preview of the pieces beforehand in the studio, but things have been so busy this time I didn't get a chance," he said.
"We are so proud of him and his paintings are outstanding as always," Bono said at last night's exhibition. "He's extraordinary."
The rockstar said he would be seriously considering bidding for one of the 28 paintings on offer to add to his growing collection.
Also in attendance were The Edge and his wife Morleigh Steinberg.
Guggi has already shown in the UK, US and Argentina in recent months.
But the talented star said that it was particularly special to see his pieces hang on the walls in Dublin again.
"This is my home town, I come from here and it's always particularly special when an exhibition is here," Guggi said.
"I'm surprised and flattered by the turnout, but it is fantastic."
It was also a family occasion for Guggi, who arrived with his wife Sibylle and their four boys, Noah, Eliah, Caleb and Gideon.
In addition to U2, there was a great turn out from the art world, as Brian Maguire, Jim Fitzpatrick and Felim Egan popped by.
Other luminaries, such as filmmaker Jim Sheridan, Michael Mortell, the Gate Theatre's Michael Colgan and model Emma Waldron were in attendance.