Amy Winehouse Back in Rehab

Amy Winehouse has checked into rehab again, her rep confirms.

The singer "has embarked on a treatment program at the Priory Clinic," her rep tells People.com in a statement. "She wants to be ready for performances in Europe this summer and decided to seek an assessment. She will remain at the Priory on doctors' advice."

She was convinced to check into the Priory clinic on Wednesday by her father, Mitch.

"Her dad sat her down and said 'I think you're drinking too much again.' So she agreed to go an assessment to stop it becoming a bigger problem," an unnamed friend told the site.

The same friend says she downed a miniature bottle of Smirnoff vodka on her way to the clinic "in typical Amy style." This report is repeated across multiple sites.

She kicks off a concert series in Europe on June 18, and the source says she will be out of rehab in time.

"She's determined, and this is all off her own back," said the friend. "It's just a lapse. There are ups and downs on the road, and there have been mostly ups recently. But this is a down and she's done the right thing and gone to rehab."

Winehouse has been to rehab at least four times.

She won five Grammys for her Back in Black album in 2008, which includes her hit song, "Rehab."