A pop star and a former prime minister make an unusual pair on paper. That's exactly why Katy Perry and Justin Trudeau are a useful case for asking what astrology can add to a relationship story, and what it can't.
The quick sign answer: she's a Scorpio, he's a Capricorn, and the signs are usually called compatible. Two dates carry more detail than two signs, and some of it points in different directions.
What's on the record
Everything here about the relationship comes from one source: ELLE's Katy Perry and Justin Trudeau relationship timeline, by Aimée Lutkin and Alyssa Bailey, which carried a September 2, 2026 date when we read it. In outline, ELLE reports:
- July 28, 2025: a publicly reported outing in Montreal, a walk in a park and dinner. ELLE notes that this alone wasn't an announcement.
- December 6, 2025: an Instagram carousel Perry posted from Japan that included Trudeau, which ELLE treats as a public presentation of the relationship.
- June 8, 2026: a joint red-carpet appearance at the Tribeca premiere of the concert film from Perry's Lifetimes Tour.
- September 2026: ELLE's timeline reproduces a People interview in which Perry describes meeting Trudeau while she was on tour, and his support at her shows.
That last point is Perry's account as reported by ELLE. We didn't read the original People interview, open the post or watch any footage, and this isn't October news. Nothing below is about their private lives or where things go next.
How the charts were compared
Both birth dates come from their Wikipedia infoboxes: Katy Perry was born on October 25, 1984, in Santa Barbara, California; Justin Trudeau on December 25, 1971, in Ottawa, Ontario. Lunara's catalogue holds a stored birth time for each, but this pair reading doesn't use either one. It's built from the dates alone.
So we sampled each person's local birth day at 25 times and compared every pairing, 625 in all, using the same Swiss Ephemeris calculation as the rest of the site. A contact only counts here if it held across all 625. The limits were 8° for a conjunction, 6° for a square and 4° for a sextile.
Two Suns, almost exactly sixty degrees apart
Perry's Sun sits at about 2–3° Scorpio. Trudeau's sits at about 3–4° Capricorn. That makes a sextile, and across every sampled pairing it was never more than 1.7° from exact.
Here the sign verdict and the chart agree, but the degree says more: many Scorpio–Capricorn pairs are born far apart within their signs, while these two Suns land near the same point. A sextile is read as an easy, cooperative contact: two different ways of being serious about something, Scorpio's depth and Capricorn's long view, that can sit side by side without much strain.
Questions for your own pair:
- What do you each take seriously that the other doesn't need explained?
- Where do your ambitions run in parallel rather than in competition?
Her Sun, his Venus: the contact that asks for effort
Trudeau's Venus sits at about 2–4° Aquarius. That's a square to Perry's Sun, within 1.6° in every sampled pairing, and just as tight as the friendly sextile above.
In synastry, Venus is read as what someone values and how they show affection, and the Sun as the other person's core sense of self. A square is a contact of friction, not failure. One reading: what he values, cool and principled in Aquarius, doesn't automatically match how she wants to be met, intense and personal in Scorpio. The work is translating rather than assuming.
This is the part a Scorpio–Capricorn sign verdict leaves out entirely. The same two charts hold an easy contact and a demanding one at almost the same strength.
Questions for your own pair:
- When you show care, is it in the way the other person actually notices?
- What do you value that you've assumed, but never said, your partner shares?
Her Jupiter on his Sun
Perry's Jupiter sits at about 8° Capricorn, conjunct Trudeau's Sun. This one is wider, between 4.0° and 5.2° across all pairings, so it's a softer contact than the other two.
Jupiter is read as encouragement, generosity and the urge to make something bigger. On someone's Sun, it's often described as one person making the other feel more confident and seen.
There's a useful mismatch here. In the account ELLE reports, the support runs from him to her, at her shows. The symbol points the other way. That doesn't make either wrong: a chart offers images to think with, and doesn't line up with a real story fact by fact.
Questions for your own pair:
- Who does the encouraging in your relationship, and is it as one-way as it looks?
- What has your partner helped you take on that you'd have avoided alone?
Support versus assumption
The reported facts are about public appearances and one account of support. The chart is about symbols computed from two birth dates. Keeping those apart is the useful habit to bring to your own relationship:
- What's observed: what each of you has actually said or done.
- What's assumed: what you've filled in about the other person's motives.
- What's symbolic: what a chart suggests you might look at, which is a prompt, not a verdict.
There's no compatibility score here and no prediction. Nobody's sign decides whether two people belong together.
Method and limits
- Sources: ELLE timeline (Aimée Lutkin and Alyssa Bailey; September 2, 2026 label as read) for the relationship chronology; Wikipedia infoboxes for birth dates and places.
- Calculation: each local civil day sampled 25 times (hourly from 00:00 to 23:00, plus 23:59), in Santa Barbara time and Ottawa time; all 625 cross-chart pairings compared. Sampled ranges, not a guarantee for every minute.
- Not used: Moons, Ascendants, Midheavens and houses for both people, even though Lunara stores birth times for them. No personal planet changed sign during either birth day.
Try it with your own pair
Their single-chart profiles are at Katy Perry's natal chart and Justin Trudeau's natal chart.
To see how your own two charts meet, compare your two charts with the birth times you actually know, and leave an unknown time blank. If you want the longer automated symbolic reading of your pair, you can see the sample and current price before paying.
Text written with AI assistance. Relationship details are paraphrased from ELLE; Lunara did not read the original People interview, open the posts or watch footage.