Mariska Hargitay, star of Law & Order: SVU, has shared a devastating tribute to friend and co-star Ned Eisenberg, who died aged 65 on Sunday.READ: Law and Order star Ned Eisenberg dies aged 65 - detailsMariska and Ned both first appeared in the hit US drama in 1999 and on Wednesday, the 58-year-old actress took to Instagram to share the news to her 2.4 million followers, along with a touching and heartfelt message remembering her colleague.WATCH: Ali Wentworth made a surprise appearance on The Drew Barrymore Show to surprise her BFF Mariska Hargitay"My heart is so full of sadness over the loss of our dear, dear Ned Eisenberg," she wrote, before adding: "What a light and what a love. And such a first-rate actor, which pales next to him as a first-rate human.READ: See the cast of Law & Order: SVU and their real-life partnersMORE: Law & Order fans sent into overdrive as Sam Waterston teases 'surprise' return of major character"We will remember him always, with his bright mischievous smile and his open-wide heart.