Melissa Sue Anderson played Mary Ingalls on the series Little House on the Prairie. The show catapulted her into instant fame and many saw her as the softspoken Mary in real life. Fans were surprised when Melissa began dating a much older man. He was none other than Frank Sinatra Jr. They met when she appeared on The Love Boat. She appeared in an episode of The Love Boat during the height of her fame. The episode had a Halloween theme and she dressed up as Cinderella. Her Prince Charming was played by Frank Sinatra Jr. They hit it off right away, despite their age difference. She was a teen and he was in his early 30s. Melissa Sue Anderson dated Frank Sinatra Jr. THE LOVE BOAT, (l to r, top) Patrick Wayne, Rhonda Bates, Christopher George, Bernie Kopell, Carolyn Jones, Ted Lange, (l to r, bottom) Lauren Tewes, Frank Sinatra, Jr., Gavin MacLeod, Melissa Sue Anderson, Joan Van Arkin 'Cindy\/Play by Play\/What's a Brother For?' (Season 3, Episode 8, aired October 27, 1979) 1977-86 \/ Everett Collection Melissa revealed in her memoir, \u201cWe became friends at that time, but did not start actually dating until two years later. Good thing, since I was just 16 when we met \u2013 what a scandal that would have been.\u201d RELATED: Melissa Sue Anderson Of \u2018Little House On The Prairie\u2019 Reveals Why She Left Hollywood For Good 'LITTLE HOUSE ON THE PRAIRIE,' Melissa Sue Anderson, Season 3, 1974-1983 \/ Everett Collection She continued, \u201cFrank Jr.\u2019s family is a great bunch. His mother, Nancy, is a little dynamo, and what a cook! \u2026 Tina was most like their father \u2013 passionate and headstrong. Nancy was soft spoken and very sweet. I had the pleasure of spending some nice evenings \u2013 not to mention great dinners \u2013 with them.\u201d From left, Frank Sinatra, Jr., Frank Sinatra, at the Americana Hotel in New York, September 12, 1963 \/ Everett Collection Despite their love, eventually, they moved on. Melissa is now married to Michael Sloan and they have two children together. Sadly, Frank died in 2016. She was very lucky to spend time with that famous family! In conclusion, watch Melissa on The Love Boat below: https:\/\/www.youtube.com\/watch?vFPFXPwXoCRA Here's our deep dive into some behind-the-scenes info about\u00a0Little House on the Prairie! \ufeff For more of these throwback videos, check out our YouTube Channel!