Jackiey Budden, who is the maternal grandmother of Bobby, was apparently secretly watching from the audience when Bobby came up to accept his Rising Star award.
Jackiey is said to have told fans outside the event how she had got audience tickets to watch the ceremony.
According to the Sun, she is claimed to have alluded to a row with Jeff, who was previously in a two-year relationship with her late daughter Jade, during which time they welcomed 20-year-old Bobby and his brother Freddie, 19.
Speaking to fans, Jackiey was allegedly heard saying: “I’m so proud of him [Bobby]. He’s incredible.
“They didn’t know I was there. I didn’t allow them to know I was there.
“I didn’t want to see their dad. He’s a c**k,” she added.
“But I’m going to wait until they’re older before I let rip.”
When Bobby came up to the stage to accept his award on Tuesday night, he paid tribute to his dad Jeff.
He said: “This actually has very, very, very little to do with me and everything to do with my Dad.
“Over the course of the last 20 years, I’ve consistently heard him say ‘because I can’.
“It was a mantra, or a motto of his. And him just saying that – because I can! Why not?”
Bobby’s mum Jade, who rose to fame on Big Brother in 2002, died aged 27 in March 2009 after getting diagnosed with cervical cancer.
Speaking to fans on Instagram in 2021, Bobby revealed he had gotten back in touch with his grandmother Jackiey after losing contact with her.
“I didn’t see her for ages – for way too long – but I went to see her twice recently,” he confirmed.
“And honestly if there’s one woman you shouldn’t underestimate it’s my nan. Honestly, she’s like a wizard! It’s nuts.”