Britney Spears’ ex-husband Sam Asghari took a vicious swipe at Kevin Federline over his upcoming tell-all book, calling the dad of six a “professional father.”

In a clip shared by TMZ Saturday, a photographer asked the former personal trainer what he thought of Federline’s upcoming book, which will “detail his marriage with Britney.”

“Well, he was a professional father,” he replied while walking outside West Hollywood hotspot The Abbey on Saturday, cheekily adding that the memoir “would be the first book that’ll tell you how to be a professional father.”

Federline — who was married to Spears, 43, from 2004 to 2007 — announced his upcoming memoir, “You Thought You Knew,” earlier this month.

Per the Daily Mail, the former backup dancer — who shares sons Sean Preston, 19, and Jayden James, 18, with Spears — wrote in a press release that the book will uncover personal details about their “highly publicized marriage.”

“This book is extremely intimate and transparent,” Federline wrote in the release. “I achieved my biggest dreams, dealt with crushing heartbreak and endured constant ridicule, all while becoming the father my children needed as they experienced non-stop emotional turbulence.”

The book is set for release on Oct. 21.

Federline, 47, famously took custody of their sons after the marriage ended, and collected $20,000 a month in child support from the pop princess until November 2024 — when both sons were past the age of 18.

Following the ill-fated union, which saw Spears endure a highly publicized meltdown amid the end of her marriage, Federline went on to marry Victoria Prince, with whom he shares two daughters. He also shares two grown children with ex-girlfriend Shar Jackson.

Spears was briefly married to childhood friend Jason Alexander in 2004, though the union was quickly annulled. Years after her split from Federline, she went on to date Asghari after filming her “Slumber Party” music video with him.

In May 2022, following their 2021 engagement, the former couple endured a miscarriage. “It is with our deepest sadness we have to announce that we have lost our miracle baby early in the pregnancy,” they said in a joint statement at the time.

“This is a devastating time for any parent. Perhaps we should have waited to announce until we were further along. However we were overly excited to share the good news.”

Spears went on to marry Asghari in a star-studded ceremony in June 2022, only to have it end in divorce in 2024.

Asghari, 31, who is now dating Brooke Irvine, appears to have residual loyalty for his famous ex-wife. “The Traitors” personality told Page Six in January that he wishes his ex-wife “the best,” despite their failed marriage.

“I think that the number one factor of a partner is to be there for one another, no matter what,” he added.