Shaquille O’Neal has until his 51st birthday in March to lose 20 pounds.
The former NBA player has already lost 40 pounds, he told Entertainment Tonight while speaking to the outlet about his upcoming virtual reality New Year’s Eve countdown special, The Shaq-tacular Spectacular.
“I lost 40 pounds,” O’Neal said. “I need to lose about 20 more, but impressive. Imma get real chiseled up and do an underwear ad with my sons.”
O’Neal and his ex-wife Shaunie O’Neal share four children together: sons Shareef and Shaqir and daughters Amirah and Me’arah. The athlete also has a stepson, Myles, from Shaunie’s previous relationship, and a daughter, Taahirah, with his former girlfriend, Arnetta Yardbourgh.
RELATED: Shaquille O’Neal Taps Snoop Dogg and Diplo for His ‘Fun House’ Super Bowl Party
The former Lakers player — who turns 51 on March 6 — told ET he got some blood work back that led him down the path of a cleaner diet.
O’Neal said because he was an athlete he didn’t pay close attention to what he was eating. Now, aside from his diet (he’s working on eliminator bread and soda), he said he also takes supplements and drinks shakes.
Never miss a story — sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.
“The weight just fell off. I’m not at 100 percent ninja mode yet. I’m still 75 percent,” O’Neal told Entertainment Tonight.
RELATED: Shaquille O’Neal ‘Believes’ in Nepotism—but His Kids Need to Show Him a ‘Business Plan’
O’Neal advised anyone who wants to get healthier to start by walking, at least 30 minutes a day.
His goal? “I think I could get the Marky Wahlberg look,” he said. “I want to be known as the Black Mark Wahlberg.”
O’Neal opened up about parenting his six children in a November cover story for PEOPLE.
He said he hopes that when the day comes when he finds himself “checking into the old folks home,” his children will be “running what I started” and continuing to contribute to the “generational wealth” he’s created throughout his career.
“I’m caring, I’m funny. I’m honest — and I teach by example,” he said of his parenting style. “I can tell my kids to go get an education, but I’m the example.” O’Neal said his kids “are way smarter” than he is and more capable of succeeding in school, adding: “I did it, and I’m not that smart.”