The feline, who was a regular feature on her Instagram, died in June.
Two weeks ago, Beckinsale showed off her first tattoo tribute – a picture of him on a forearm.
Now, the star has another in honour of Clive – his eyes on the back of a shoulder.
Under the picture, she wrote: “How can a light that burned so brightly suddenly burn so pale? Love you always.”
The Underworld star announced Clive’s death on Instagram earlier this year, alongside a photograph of her hugging him while he was wrapped in a pink fluffy jacket.
“Every single part of my house feels like he should be in it,” the Londoner wrote.
“If anyone is expecting to hear from me, you may not for a bit and I’m sorry. My heart is absolutely and totally broken.”
She added: “I don’t have it in me to make a montage or even look at pictures of him yet.”
Clive became somewhat of an Instagram star after Beckinsale started posting videos and photos of the pair to her almost six million Instagram followers during the Covid pandemic.
In one video, Beckinsale accessorised Clive with googly eye stickers as the two bopped along to will.i.am and Britney Spears’ Scream & Shout track.
In another, she asked him questions about his life, acting as a hairdresser, while she chopped his mane.
Clive also celebrated his 17th birthday and played a little Cat Stevens for his fans.
Meanwhile, last month Beckinsale – who celebrated her 50th birthday in July – revealed her mother Judy was ill in hospital back in the UK.