Sun-sign compatibility · two fire signs · the same sign
Aries and Aries compatibility
Two Aries Suns are a conjunction by sign: the same element, fire, the same modality, cardinal, and the same month of the year. Astrology reads the same sign as the angle of likeness, and the pairing as the one in which two people recognise themselves in each other first.
This year the Sun is in Aries from 20 March to 20 April, so both people were born in the same few weeks of the year, in whatever years. 4 famous couples in StarMap's dataset are two Aries Suns, where chance would give about 3.4: Robert Downey Jr. and Sarah Jessica Parker, Sarah Jessica Parker and Matthew Broderick and Steve McQueen and Ali MacGraw among them. Among the 537 couples with both Sun signs certain, that makes this the 68th most common pairing of the 78. A Sun sign is one placement of ten, and the two whole charts say far more than the two signs.
Each sign has its own page: Aries, with its dates to the minute, its traits and the famous people born under it.
What astrology reads for Aries and Aries
Two people with the Sun in the same sign share a way of being seen. Astrology reads the Sun as the part of a person that wants to be recognised, and when two Suns sit in one sign each already understands what the other is asking for: the same kind of praise, the same kind of attention, the same idea of what a good day looks like. The first weeks tend to feel like being understood without explaining.
The tradition is also candid about the cost. What two people share they also compete over, and a pair with the same Sun sign can find that the thing they both want most is the thing there is only one of in the room. The reading is that the sign's strengths are doubled and so are its blind spots, and that the rest of the two charts, the Moons and the rising signs above all, decides whether the likeness feels like company or like a mirror.
Two fire signs
Two fire signs are read as two people who both run hot: quick to enthusiasm, quick to act, and happiest when something is happening. The tradition reads the pairing as warm and loud, with more adventures than most and a tendency to burn through plans before either has thought about the next one. Neither is much inclined to be the steady one, and astrologers read the question for a fire pair as who notices when the pace needs to drop.
Two cardinal signs
Both signs are cardinal, the starting signs of their seasons, and the tradition reads two cardinal people as two leaders in one relationship: both want to set the direction, and the question is who goes first on which day. The reading is of a pair that gets a great deal started and has to decide on purpose who finishes.
These are readings of the Sun signs alone, written for reflection and entertainment. They describe tendencies the tradition assigns to an angle, not two people, and they do not say whether a pair lasts.
Aries in love
Aries
In love, Aries pursues. Interest is shown early and plainly, the chase matters, and the sign is at its best with a partner who can hold their own rather than one who gives way. What it needs to learn is patience: desire arrives before tenderness, and the relationship lasts when the second catches up with the first.
532 famous people have the Sun in Aries for certain: every Aries Sun, each with a birth chart.
Famous Aries and Aries couples
Of the 537 spouse and partner pairs in StarMap’s dataset whose Sun signs are both certain, 4 are two Aries Suns. From the share of each sign among every couple’s members, chance alone would give about 3.4, a ratio of 1.19, which makes this the 68th most common pairing of the 78. Their sky match, from the angles between the two charts, averages 77 out of 100 against 67 for every couple counted. With about seven couples a cell, a ratio between a half and double is what chance produces; the counts describe the dataset, not the signs.

86Robert Downey Jr. and Sarah Jessica Parker
Listed as partners, 1984 to 1991

70Sarah Jessica Parker and Matthew Broderick
Married in 1997

79Steve McQueen and Ali MacGraw
Married in 1973 · marriage ended in 1978

74Mandy Moore and Zach Braff
Listed as partners, 2004 to 2006
All famous couples, each scored from both birth charts.
Both signs in one chart
A chart with the Sun and the Moon both in Aries belongs to someone born near a new Moon in Aries season: the sign's way of being seen and its way of feeling are the same.
Sun in Aries, Moon in Aries: 25 famous people
Only people whose Sun and Moon signs do not depend on an unknown birth time are counted. The Moon in Aries has a page of its own.
Questions people ask
Are two Aries Suns compatible?
By Sun sign alone, astrology reads two Aries Suns as a conjunction: the same element and modality, with the sign's strengths doubled and its blind spots too. That is a reading of one placement of ten and not a verdict on two people. In StarMap's dataset of famous couples, 4 are two Aries Suns, against about 3.4 that chance would give, a ratio of 1.19. The angles between two whole charts, Moon to Moon and Venus to Mars among them, say more than the Sun signs can; the comparison is free on StarMap.
How many famous couples are two Aries Suns?
4 of the 537 couples in StarMap's dataset with both Sun signs certain, Robert Downey Jr. and Sarah Jessica Parker, Sarah Jessica Parker and Matthew Broderick and Steve McQueen and Ali MacGraw among them. Chance alone would give about 3.4, which makes it the 68th most common pairing of the 78. Their sky match, from the angles between the two charts, averages 77 out of 100 against 67 for every couple counted.
Who has the Sun and the Moon both in Aries?
25 people in StarMap's dataset have the Sun in Aries and the Moon in Aries, Celine Dion, Marlon Brando and Jenny Slate among them. The Moon's sign depends on the day and often on the hour of birth, so only people whose Moon sign is certain are counted.
Sun signs are computed from the Sun’s position with the astronomy-engine ephemeris, checked against Swiss Ephemeris, in the tropical zodiac. Birth data and relationship data come from Wikidata; birth times, where StarMap has one, from Astro-Databank with their Rodden rating. A couple is counted only when the Sun was in one sign for the whole of each birth date. Readings describe what the tradition assigns to an angle, for entertainment and self-reflection; StarMap predicts nothing. Compare two whole charts.
Photo credits (10 photos from Wikimedia Commons)
Each link opens the photo’s page on Wikimedia Commons, which states its author and licence.