The singer admitted that he had his doubts over the romance, with 19-year-old Sofia being 15 years younger than 34-year-old father-of-three Scott.
Speaking to Us Weekly, Lionel shared: “Have I been in shock? I’m the dad, come on.
“I’m scared to death – are you kidding me?”
Back in May Sofia denied that she was dating Scott, insisting that she was just friends with the Keeping Up With The Kardashians’ reality star.
However, the pair were filmed passionately kissing on a friend’s Snapchat account just a few weeks ago and also packed on the PDA on a recent trip to Mexico, with the couple looking happy and relaxed in each other’s company.
Speaking to People, a source added: “Scott and Sofia are inseparable. They are spending every day together. Sofia seems smitten.
“It’s obvious that she looks up to Scott. She constantly giggles around him. They are very flirty.
“Scott takes care of her, opens the car door and pays for everything.”
After she and Scott were papped cuddling on a yacht in Cannes five months ago, Sofia tweeted: “Just so everyone can get their panties out of their a*ses, Scott and I are just homies.”
Scott was previously linked to 19-year-old actress Bella Thorne, with the Internet going into meltdown when Scott was papped seemingly groping Bella’s breast before being pictured with an ex just hours later.
It was reported at the time that Bella had been left feeling “used” by Scott, however, she later claimed that she’d decided to step away from Scott’s wild lifestyle – even defending the infamous picture.
Speaking of the snap, Bella said: “Honestly, my nipple came out of my bikini and he tried to fix it for me and it looks like he’s grabbing my boob.”
Scott shot to fame in ex-girlfriend Kourtney Kardashian’s reality TV show back in 2007, with the pair splitting in 2015 after 10 years together.
Together, he and Kourtney have seven-year-old Mason, five-year-old Penelope, and two-year-old Reign, with the pair remaining on good terms for the sake of their children.