Among Shar Jackson’s guest list for her 32nd birthday party: family, friends and Kevin Federline.

The father of four - including two children with Jackson - was at Las Vegas’s Blush Nightclub on Friday helping his ex celebrate, and even giving her a birthday hug.

“We were friends before we were a couple and we’re always going to be friends,” Jackson told PEOPLE at Wynn Las Vegas before entering the party. “We have two amazing kids together. Kevin is my boy.”

Jackson, however, insists that there is no talk of rekindling the flame. “We have passed that stage.”

Jackson’s party was the first stop for Federline in night that saw him dropping by newly opened Lavo, Tao and Prive Las Vegas, where Jackson also joined him.

After seeing each other for the third time in 12 hours, Federline took a break from partying at a table in the club’s kitchen, then headed to the deejay booth to publicly wish Jackson a happy birthday into a microphone.

While rumors persist that Federline’s other ex, Britney Spears, may be planning a performance at the MTV Video Music Awards next month, she has a backer in Jackson.

“I hope she does it, I hope she goes for it and kills it,” Jackson said.

He may have partied till nearly dawn, but parenting was on the mind of Kevin Federline Friday night into Saturday morning - capping a week in which he and ex Britney Spears seem destined for a custody showdown.

“Kevin was in a great mood and even talked about a new song he is working on, called ‘Daddy’s Home,’ ” says a source at Mansion on South Beach - where K-Fed (as host) and his party of 10 and a security guard stayed until 4 a.m. Saturday, following a late dinner at Miami’s Michy’s, an intimate and upscale restaurant.

“He has put a lot of time and effort into writing and rehearsing it, but says it is not quite ready yet,” the source tells PEOPLE.

Although multiple bottles of champagne were sent to Federline, he preferred to drink water. Not that the bubbly went to waste - he sprayed an entire bottle on the dancing crowd.

Scrubs star Zach Braff and Donald Faison, with Cacee Cobb, Jessica Simpson’s former assistant, came late and hung with Federline while he danced with his group of friends, including one guy from his hometown.

Good Dance Moves

“Kevin is a great dancer with some very complicated moves,” says another source at Mansion. “He wasn’t with any one girl in particular. He was friendly and nice to everyone and in a wonderful mood.”

Federline, 30, had been seen in the late afternoon checking into the Gansevoort Hotel on South Beach, where he asked staffers to call him “Kevin” and even signed autographs.

“Kevin seemed happy and was very gracious,” says an eyewitness. “He stopped and took photos with anyone who asked.”

• With additional reporting by JULIE KAY and DEBI SPRINGER

Kevin Federline is the new father of the year!

Just in time for Father’s Day, Prive Las Vegas will award the proud papa of four his “father of the year” status at a party he is slated to host there June 13.

Sources tell PEOPLE he will be awarded the title during a presentation at the club.

The unofficial honor is Federline’s second such recognition in a relatively short time. Last November, Details magazine also anointed him father of the year - an honor he shared with onetime Anna Nicole Smith boyfriend Larry Birkhead.
- Mark Gray