Age is only a number ... right?
Robin Thicke's much younger girlfriend April Geary took to Instagram on Monday to share a shot of her and the "Blurred Lines" singer celebrating the holidays in St. Barts.
In the pic, Geary rocks a barely-there peach string bikini as she cuddles up to her 38-year-old beau. Thicke looks cool and casual sporting a black button down and black swim trunks. FYI: The blonde beauty just celebrated her 21st birthday this month.
"Lucky to be in love with my best friend," she captioned the candid snapshot.
The pop star and Geary first went public with their relationship back in May at the Cannes Film Festival ... just two months after Robin and ex-wife Paula Patton divorced.
Though the former flames share 5-year-old son Julian Fuego together, it's great to see that both stars have moved on with their lives.
What do you think about Robin's bikini-clad lady love? Sound off below and check out the gallery above to see more celebrity couples with big age gaps!