Celebrity Parents Greg Olsen's Son, 8, Rings Hospital Bell After Heart Transplant: 'We Are Finally Whole Again' Greg Olsen's 8-year-old son T.J. — who was born with a rare condition called hypoplastic left heart syndrome — received a new heart on June 4 By Gabrielle Chung Published on June 16, 2021 06:36 PM Share Tweet Pin Email Photo: Greg Olsen/Instagram. Inset: Moses Robinson/Getty Greg Olsen's 8-year-old son T.J. has hit a major milestone in his road to recovery after undergoing a heart transplant. On Wednesday, the former NFL tight end, 36, shared a video of T.J. ringing a bell at the hospital — an act that typically signifies the end of a long treatment — nearly two weeks after he had received a new heart. Olsen, who also shares T.J.'s twin sister Talbot and older son Tate with wife Kara, wrote on his Instagram, "Ever since TJ was admitted into the ICU a little less than a month ago in heart failure, we would lay in bed at night and talk about 'ringing the bell.'" "We didn't know what that journey would look like or how long it would take, but he promised @karaolsen29 and I that he was going to ring it," he continued. Greg Olsen's Son, 8, Shares Video Message After Heart Transplant: 'Thank You for Thinking of Me' Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday The retired athlete went on to praise T.J. — who was born with a rare condition called hypoplastic left heart syndrome, meaning he had just half a heart — for his "positive attitude and selflessness" throughout his health struggles, writing that his son "has been an inspiration to us all." "Never did he feel sorry for him self or play the victim," Olsen explained. "All he did was talk about what the future held and the things he looked forward to doing." "Today we 'rang the bell', and for the first time our family whole again," he added. The father of three concluded his message with a note to "everyone who prayed for our little buddy and sent us words of encouragement and support." "All we can say is THANK YOU and WE 💚 YOU ALL," he wrote. Greg Olsen/instagram In late May, Olsen revealed that T.J. had been hospitalized due to issues with his heart. T.J. underwent heart transplant surgery on June 4 after the family was notified the night before that a donor match was found. At the time, Olsen said that "day we have prayed for has arrived." "We were alerted last night that there was a donor match for TJ to receive his heart transplant," he wrote alongside a photo of himself and his wife holding their son's hand at the hospital. "Walking our little boy, with tears of hope and fear in our eyes, was one of the toughest moments of our lives." Olsen posted a video message from T.J. three days after the surgery. In the clip, the young boy thanked supporters for "thinking of me." "Thank you for praying with me," T.J. said. "We love you guys, bye." Greg Olsen Shares Moment Son, 8, Told Siblings He Got Heart Transplant Donor: 'Forever Grateful' On Thursday, Olsen shared a throwback video from when T.J. broke the news to his brother and sister that he had found a donor. The heartwarming footage showed Talbot and Tate happily clapping and hugging T.J. "Exactly 1 week ago, we were notified that we received an offer for a heart transplant," Olsen wrote at the time. "A special angel donor, somewhere, allowed Tj to share the news himself w/ Tate and Talbot. We are forever grateful."