Less than two years ago Jessica Simpson and Nick Lachey were celebrating their third wedding anniversary in Italy, but the no-longer-newlywed Simpson recently went back to the country – this time to Rome with her singer squeeze John Mayer.

"She's really happy," says longtime Simpson friend and New York City colorist Rita Hazan, who touched up the singer's brunette locks before her departure.

While in Rome, Mayer and Simpson booked a top floor suite at the Hotel de Russie – the same hotel where some of Tom Cruise and Katie Holmes's guests stayed during the couple's November nuptials.

On March 8, the lovebirds lunched at Dal Bolognese restaurant. "He was smiling very much and she was giggling a lot," says a source at the eatery. "They held hands for much of the time and had eyes only for themselves."

The couple, who left the restaurant hand-in-hand, attracted some attention but didn't seemed phased, says the source. "When they walked out there were three or four paparazzi waiting for them," says the source. "They didn't seem to mind having their pictures taken."

Next stop, Via Condotti, Rome's most exclusive shopping street, where Mayer, 29, and Simpson, 26, strolled among the crowd. They stopped to shop at Fendi, Gucci, Valentino and even La Perla's luxury underwear shop.

Between all the shopping and eating out, Mayer, found time to post panoramic photo montages of his visit on his blog.

"Sometimes you try to shoot subjects way too expansive for any camera lens," wrote Mayer, who took a series of eight photos to try to capture the grandeur of Rome's Colosseum. "Some people call this trip a 'Roman Holiday.' But I call it a very expensive way to get new desktop pictures for my Mac."

The couple left Rome Tuesday, according to a source who says, "They're back in L.A. now. They had a fantastic trip."